Elite Green Protein Ingredients & Drug Interactions

Theoretically, black psyllium might reduce the effects of carbamazepine and increase the risk for convulsions.
Theoretically, black psyllium might reduce carbamazepine absorption. A preliminary study using blond psyllium reported decreased carbamazepine bioavailability due to binding of the drug to psyllium, as well as reduction of available fluid in the gut for dissolution of the drug. This interaction may also occur with black psyllium.

Theoretically, taking black psyllium at the same time as lithium might reduce lithium absorption.
The fiber in black psyllium might reduce lithium absorption and plasma levels. Some case reports describe a reduction in plasma lithium levels with concomitant administration of blond psyllium. This was reversed when psyllium was stopped. This interaction may also occur with black psyllium.

Theoretically, black psyllium might increase the therapeutic and adverse effects of metformin.
Animal research shows that concurrent consumption of blond psyllium with metformin slows and increases the absorption of metformin. This interaction may also occur with black psyllium. To avoid changes in absorption, take psyllium 30-60 minutes after metformin.

Theoretically, taking black psyllium at the same time as olanzapine might reduce olanzapine absorption.
The fiber in black psyllium might decrease the absorption of olanzapine. A single case report describes a reduction in the effectiveness of olanzapine when it was concomitantly administered with an unspecified type of psyllium 3 grams orally twice daily. This effect was reversed when psyllium was stopped.

Theoretically, taking black psyllium at the same time as digoxin might reduce digoxin absorption and decrease digoxin levels.
Psyllium might bind digoxin in the gut. However, some clinical evidence suggests that psyllium does not impact digoxin absorption.

Theoretically, taking black psyllium at the same time as ethinyl estradiol might alter levels of estradiol.
Concurrent use of blond psyllium with ethinyl estradiol results in a slight increase in the extent of ethinyl estradiol absorption and a slower rate of absorption. This is unlikely to be clinically significant.

Theoretically, psyllium might increase, decrease, or have no effect on the absorption of oral drugs.
Psyllium seems to have variable effects on drug absorption. To avoid changes in absorption, take psyllium 30-60 minutes after oral medications. Animal research shows that blond psyllium delays and increases the absorption of metformin and ethinyl estradiol. Case reports and animal research suggest that blond psyllium might reduce absorption of lithium, digoxin, olanzapine, and carbamazepine. Finally, some pharmacokinetic studies show that psyllium does not affect the absorption of levothyroxine or warfarin. Although many of these studies evaluated blond psyllium, the fiber content in black psyllium may have similar effects.

Theoretically, taking ashwagandha with antidiabetes drugs might increase the risk of hypoglycemia.
There is preliminary clinical evidence suggesting that ashwagandha might lower blood glucose levels. Theoretically, ashwagandha might have additive effects when used with antidiabetes drugs and increase the risk of hypoglycemia.

Theoretically, taking ashwagandha with antihypertensive drugs might increase the risk of hypotension.
Animal research suggests that ashwagandha might lower systolic and diastolic blood pressure. Theoretically, ashwagandha might have additive effects when used with antihypertensive drugs and increase the risk of hypotension.

Theoretically, taking ashwagandha might increase the sedative effects of benzodiazepines.
There is preliminary evidence that ashwagandha might have an additive effect with diazepam (Valium) and clonazepam (Klonopin). This may also occur with other benzodiazepines.

Theoretically, taking ashwagandha might increase the sedative effects of CNS depressants.
Ashwagandha seems to have sedative effects. Theoretically, this may potentiate the effects of barbiturates, other sedatives, and anxiolytics.

Theoretically, taking ashwagandha with hepatotoxic drugs might increase the risk of liver damage.
Ashwagandha has been linked to cases of acute hepatitis, liver failure, hepatic encephalopathy, autoimmune hepatitis, the need for liver transplantation, and death due to liver failure.

Theoretically, taking ashwagandha might decrease the effects of immunosuppressants.
Ashwagandha has demonstrated immunostimulant effects in humans. Animal research has shown that ashwagandha can attenuate the immunosuppression caused by cyclophosphamide.

Ashwagandha might increase the effects and adverse effects of thyroid hormone.
Concomitant use of ashwagandha with thyroid hormones may cause additive therapeutic and adverse effects. Preliminary clinical research and animal studies suggest that ashwagandha boosts thyroid hormone synthesis and secretion. In one clinical study, ashwagandha increased triiodothyronine (T3) and thyroxine (T4) levels by 41.5% and 19.6%, respectively, and reduced serum TSH levels by 17.4% from baseline in adults with subclinical hypothyroidism.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that ashwagandha extract induces CYP1A2 enzymes.

Theoretically, ashwagandha might decrease the levels and clinical effects of CYP3A4 substrates.
In vitro research shows that ashwagandha extract induces CYP3A4 enzymes.

Some animal studies have reported that ashwagandha can enhance serotonergic transmission by altering certain serotonin (5-HT) receptors. However, there is no evidence to suggest that ashwagandha increases the risk of serotonin-related effects, and there have been no published case reports of serotonin syndrome when combined with other serotonergic drugs. Nevertheless, due to the lack of extensive studies on the matter and the fact that ashwagandha appears to affect serotonergic pathways, it would be prudent to exercise caution when combining it with drugs that affect serotonin. [References: - Effects of Withania somnifera (Ashwaga ndha) on Stress and the Stress-Related Neuropsychiatric Disorders Anxiety, Depression, and Insomnia. Curr Neuropharmacol. 2021 Sep 14; 19: 1468–1495. - A Prospective, Randomized Double-Blind, Placebo-Controlled Study of Safety and Efficacy of a High-Concentration Full-Spectrum Extract of Ashwagandha Root in Reducing Stress and Anxiety in Adults. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3573577/]

Theoretically, eleuthero may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research shows that a constituent of eleuthero, dihydroxybenzoic acid, appears to inhibit platelet aggregation. Concomitant use with anticoagulant or antiplatelet drugs might increase the risk of bleeding. This effect has not been reported in humans.

Theoretically, eleuthero might have additive effects when used with antidiabetes drugs.
Animal research suggests that certain constituents of eleuthero have hypoglycemic activity in both healthy and diabetic animals. A small study in adults with type 2 diabetes also shows that taking eleuthero for 3 months can lower blood glucose levels. However, one very small study in healthy individuals shows that taking powdered eleuthero 3 grams, 40 minutes prior to a 75-gram oral glucose tolerance test, significantly increases postprandial blood glucose levels when compared with placebo. These contradictory findings might be due to patient-specific variability and variability in active ingredient ratios.

Theoretically, eleuthero might increase levels of drugs metabolized by CYP1A2.
In vitro and animal research suggest that standardized extracts of eleuthero inhibit CYP1A2. This effect has not been reported in humans.

Theoretically, eleuthero might increase levels of drugs metabolized by CYP2C9.
In vitro and animal research suggest that standardized extracts of eleuthero might inhibit CYP2C9. This effect has not been reported in humans.

Eleuthero might increase serum digoxin levels and increase the risk of side effects.
In one case report, a 74-year-old male who was stabilized on digoxin presented with an elevated serum digoxin level after starting an eleuthero supplement, without symptoms of toxicity. After stopping the supplement, serum digoxin levels returned to normal. It is not clear whether this was due to a pharmacokinetic interaction or to interference with the digoxin assay. Although the product was found to be free of digoxin and digitoxin, it was not tested for other contaminants.

Theoretically, eleuthero might interfere with immunosuppressive drugs because of its immunostimulant activity.
Animal and in vitro research shows that eleuthero extracts have immunomodulatory effects, including increasing cellular and humoral activity.

Theoretically, eleuthero might increase levels of P-glycoprotein substrates.
In vitro research suggests that eleuthero can inhibit the multi-drug transporter protein, P-glycoprotein. However, it is too soon to tell if this is clinically important. This interaction has not been reported in humans.

Theoretically, eleuthero might increase levels of drugs metabolized by CYP2D6.
In vitro and animal research suggest that standardized extracts of eleuthero might inhibit CYP2D6. However, research in healthy human volunteers has found that taking eleuthero 485 mg twice daily for 14 days does not inhibit CYP2D6 drug metabolism.

Theoretically, eleuthero might increase levels of drugs metabolized by CYP3A4.
In vitro and animal research suggest that standardized extracts of eleuthero might inhibit CYP3A4. However, research in healthy human volunteers has found that taking eleuthero 485 mg twice daily for 14 days does not inhibit CYP3A4 drug metabolism.

Theoretically, eleuthero might decrease levels of drugs metabolized by OATP.
In vitro research suggests that eleuthero inhibits OATP2B1, which might reduce the bioavailability of oral drugs that are substrates of OATP2B1. Due to the weak inhibitory effect identified in this study, this interaction is not likely to be clinically significant.

Ginger may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs. However, research is conflicting.
Laboratory research suggests that ginger inhibits thromboxane synthetase and decreases platelet aggregation. However, this has not been demonstrated unequivocally in humans, with mixed results from clinical trials. Theoretically, excessive amounts of ginger might increase the risk of bleeding when used with anticoagulant/antiplatelet drugs.

Theoretically, taking ginger with antidiabetes drugs might increase the risk of hypoglycemia.
Animal and human research suggests that ginger might increase insulin levels and/or decrease blood glucose levels.

Ginger might increase or decrease the levels of CYP3A4 substrates.
In vitro research and some case reports suggest that ginger inhibits CYP3A4 activity. Three case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking ginger and cancer medications that are CYP3A4 substrates (imatinib, dabrafenib, and crizotinib). However, the causality of this interaction is unclear due to the presence of multiple interacting drugs and routes of administration.
Conversely, other in vitro research suggests that ginger induces CYP3A4 activity, leading to reduced levels of CYP3A4 substrates. However, this interaction has not been reported in humans.

Theoretically, ginger might increase levels of losartan and the risk of hypotension.
In animal research, ginger increased the levels and hypotensive effects of a single dose of losartan. It is not clear if ginger alters the concentration or effects of losartan when taken continuously. Additionally, this interaction has not been shown in humans.

Ginger may have antiplatelet effects and increase the risk of bleeding if used with nifedipine.
Clinical research shows that combined treatment with ginger 1 gram plus nifedipine 10 mg significantly inhibits platelet aggregation when compared to nifedipine or ginger alone.

Ginger might increase the absorption and blood levels of P-glycoprotein (P-gp) substrates.
In vitro research and case reports suggest that ginger inhibits drug efflux by P-gp, potentially increasing absorption and serum levels of P-gp substrates. Two case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking ginger and cancer medications that are P-gp substrates (trametinib, crizotinib). However, the causality of this interaction is unclear due to the presence of multiple interacting drugs and routes of administration.

Ginger might increase the risk of bleeding with phenprocoumon.
Phenprocoumon, a warfarin-related anticoagulant, might increase the international normalized ratio (INR) when taken with ginger. There is one case report of a 76-year-old woman with a stable INR on phenprocoumon that increased to greater than 10 when she began consuming dried ginger and ginger tea.

Ginger might increase the risk of bleeding with warfarin.
Laboratory research suggests that ginger might inhibit thromboxane synthetase and decrease platelet aggregation. In one case report, ginger increased the INR when taken with phenprocoumon, which has similar pharmacological effects as warfarin. In another case report, ginger increased the INR when taken with a combination of warfarin, hydrochlorothiazide, and acetaminophen. A longitudinal analysis suggests that taking ginger increases the risk of bleeding in patients taking warfarin for at least 4 months. However, research in healthy people suggests that ginger has no effect on INR, or the pharmacokinetics or pharmacodynamics of warfarin. Until more is known, monitor INRs closely in patients taking large amounts of ginger.

Theoretically, taking ginger with calcium channel blockers might increase the risk of hypotension.
Some animal and in vitro research suggests that ginger has hypotensive and calcium channel-blocking effects. Another animal study shows that concomitant administration of ginger and the calcium channel blocker amlodipine leads to greater reductions in blood pressure when compared with amlodipine alone.

Theoretically, when taken prior to cyclosporine, ginger might decrease cyclosporine levels.
In an animal model, ginger juice taken 2 hours prior to cyclosporine administration reduced the maximum concentration and area under the curve of cyclosporine by 51% and 40%, respectively. This effect was not observed when ginger juice and cyclosporine were administered at the same time.

Theoretically, ginger might increase the levels of CYP1A2 substrates.
In vitro research shows that ginger inhibits CYP1A2 activity. However, this interaction has not been reported in humans.

Theoretically, ginger might increase the levels of CYP2B6 substrates.
In vitro research shows that ginger inhibits CYP2B6 activity. However, this interaction has not been reported in humans.

Theoretically, ginger might increase the levels of CYP2C9 substrates.
In vitro research shows that ginger inhibits CYP2C9 activity. However, this interaction has not been reported in humans.

Theoretically, ginger might increase levels of metronidazole.
In an animal model, ginger increased the absorption and plasma half-life of metronidazole. In addition, the elimination rate and clearance of metronidazole was significantly reduced.

Taking milk thistle with antidiabetes drugs may increase the risk of hypoglycemia.
Clinical research shows that milk thistle extract, alone or along with tree turmeric extract, can lower blood glucose levels and glycated hemoglobin (HbA1c) in patients with type 2 diabetes, including those already taking antidiabetes drugs. Additionally, animal research shows that milk thistle extract increases the metformin maximum plasma concentration and area under the curve and decreases the renal clearance of metformin, due to inhibition of the multi-drug and toxin extrusion protein 1 (MATE1) renal tubular transport protein.

Theoretically, milk thistle might inhibit CYP2B6.
An in vitro study shows that silybin, a constituent of milk thistle, binds to and noncompetitively inhibits CYP2B6. Additionally, silybin might downregulate the expression of CYP2B6 by decreasing mRNA and protein levels.

Theoretically, milk thistle might affect the clearance of drugs that undergo glucuronidation.
Laboratory research shows that milk thistle constituents inhibit uridine diphosphoglucuronosyl transferase (UGT), the major phase 2 enzyme that is responsible for glucuronidation. Theoretically, this could decrease the clearance and increase levels of glucuronidated drugs. Other laboratory research suggests that a milk thistle extract of silymarin might inhibit beta-glucuronidase, although the significance of this effect is unclear.

Theoretically, milk thistle might increase the levels and clinical effects of ledipasvir.
Animal research in rats shows that milk thistle increases the area under the curve (AUC) for ledipasvir and slows its elimination.

Theoretically, concomitant use of milk thistle with morphine might affect serum levels of morphine and either increase or decrease its effects.
Animal research shows that milk thistle reduces serum levels of morphine by up to 66%. In contrast, laboratory research shows that milk thistle constituents inhibit uridine diphosphoglucuronosyl transferase (UGT), the major phase 2 enzyme that is responsible for glucuronidation. Theoretically, this could decrease the clearance and increase morphine levels. The effect of taking milk thistle on morphine metabolism in humans is not known.

Theoretically, milk thistle might decrease the clearance and increase levels of raloxifene.
Laboratory research suggests that the milk thistle constituents silibinin and silymarin inhibit the glucuronidation of raloxifene in the intestines.

Milk thistle might decrease the clearance of sirolimus.
Pharmacokinetic research shows that a milk thistle extract of silymarin decreases the apparent clearance of sirolimus in hepatically impaired renal transplant patients. It is unclear if this interaction occurs in patients without hepatic impairment.

Theoretically, milk thistle might decrease the levels and clinical effects of sofosbuvir.
Animal research in rats shows that milk thistle reduces the metabolism of sofosbuvir, as well as the hepatic uptake of its active metabolite.

Theoretically, the milk thistle constituent silibinin might increase tamoxifen levels and interfere with its conversion to an active metabolite.
Animal research suggests that the milk thistle constituent silibinin might increase plasma levels of tamoxifen and alter its conversion to an active metabolite. The mechanism appears to involve inhibition of pre-systemic metabolism of tamoxifen by cytochrome P450 (CYP) 2C9 and CYP3A4, and inhibition of P-glycoprotein-mediated efflux of tamoxifen into the intestine for excretion. Whether this interaction occurs in humans is not known.

Theoretically, milk thistle might increase the effects of warfarin.
In one case report, a man stabilized on warfarin experienced an increase in INR from 2.64 to 4.12 after taking a combination product containing milk thistle 200 mg daily, as well as dandelion, wild yam, niacinamide, and vitamin B12. Levels returned to normal after stopping the supplement. Although a direct correlation between milk thistle and the change in INR cannot be confirmed, some in vitro research suggests that milk thistle might inhibit cytochrome P450 2C9 (CYP2C9), an enzyme involved in the metabolism of various drugs, including warfarin.

It is unclear if milk thistle inhibits CYP2C9; research is conflicting.
In vitro research suggests that milk thistle might inhibit CYP2C9. Additionally, 3 case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking milk thistle and cancer medications that are CYP2C9 substrates, including imatinib and capecitabine. However, contradictory clinical research shows that milk thistle extract does not inhibit CYP2C9 or significantly affect levels of the CYP2C9 substrate tolbutamide. Differences in results could be due to differences in dosages or formulations utilized.

It is unclear if milk thistle inhibits CYP3A4; research is conflicting.
While laboratory research shows conflicting results, pharmacokinetic research shows that taking milk thistle extract 420-1350 mg daily does not significantly affect the metabolism of the CYP3A4 substrates irinotecan, midazolam, or indinavir. However, 8 case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking milk thistle and cancer medications that are CYP3A4 substrates, including gefitinib, sorafenib, doxorubicin, and vincristine.

Theoretically, milk thistle might interfere with estrogen therapy through competition for estrogen receptors.
Animal research suggests that a milk thistle extract of silymarin binds to estrogen receptor beta.

Theoretically, milk thistle might interfere with statin therapy by decreasing the activity of organic anion transporting polypeptide 1B1 (OATB1B1) and inhibiting breast cancer resistance protein (BCRP).
Preliminary evidence suggests that a milk thistle extract of silymarin can decrease the activity of the OATP1B1, which transports HMG-CoA reductase inhibitors into the liver to their site of action, and animal research shows this increases the maximum plasma concentration of pitavastatin and pravastatin. The silibinin component also inhibits BCRP, which transports statins from the liver into the bile for excretion. However, in a preliminary study in healthy males, silymarin 140 mg three times daily had no effect on the pharmacokinetics of a single 10 mg dose of rosuvastatin.

Theoretically, milk thistle may induce cytochrome P450 3A4 (CYP3A4) enzymes and increase the metabolism of indinavir; however, results are conflicting.
One pharmacokinetic study shows that taking milk thistle (Standardized Milk Thistle, General Nutrition Corp.) 175 mg three times daily in combination with multiple doses of indinavir 800 mg every 8 hours decreases the mean trough levels of indinavir by 25%. However, results from the same pharmacokinetic study show that milk thistle does not affect the overall exposure to indinavir. Furthermore, two other pharmacokinetic studies show that taking specific milk thistle extract (Legalon, Rottapharm Madaus; Thisilyn, Nature's Way) 160-450 mg every 8 hours in combination with multiple doses of indinavir 800 mg every 8 hours does not reduce levels of indinavir.

Milk thistle may inhibit one form of OATP, OATP-B1, which could reduce the bioavailability and clinical effects of OATP-B1 substrates.
In vitro research shows that milk thistle inhibits OATP-B1. Two case reports from the World Health Organization (WHO) adverse drug reaction database describe increased toxicity in patients taking milk thistle and cancer medications that are OATP substrates, including sorafenib and methotrexate. OATPs are expressed in the small intestine and liver and are responsible for the uptake of drugs and other compounds into the body. Inhibition of OATP may reduce the bioavailability of oral drugs that are substrates of OATP.

Theoretically, milk thistle might increase the absorption of P-glycoprotein substrates. However, this effect does not seem to be clinically significant.
In vitro research shows that milk thistle can inhibit P-glycoprotein activity and 1 case report from the World Health Organization (WHO) adverse drug reaction database describes increased abdominal pain in a patient taking milk thistle and the cancer medication vincristine, a P-glycoprotein substrate, though this patient was also taking methotrexate. However, a small pharmacokinetic study in healthy volunteers shows that taking milk thistle (Enzymatic Therapy Inc.) 900 mg, standardized to 80% silymarin, in 3 divided doses daily for 14 days does not affect absorption of digoxin, a P-glycoprotein substrate.

Theoretically, moringa might increase or decrease levels of CYP3A4 substrates.
Some in vitro research suggests that moringa inhibits cytochrome P450 3A4 (CYP3A4). However, other in vitro research suggests that moringa extract induces CYP3A4 enzymes. A pharmacokinetic study in patients with HIV shows no change in the pharmacokinetics of nevirapine, which is partially metabolized by CYP3A4, when administered concomitantly with moringa leaf powder 1.85 grams daily for 14 days.

Theoretically, moringa leaf can antagonize the effects of levothyroxine.
Animal research suggests that moringa aqueous leaf extract might reduce serum triiodothyronine (T3) concentrations by inhibiting the peripheral conversion of thyroxine (T4) to T3.

Theoretically, moringa leaf extract might increase the levels and clinical effects of P-glycoprotein substrates.
In vitro research shows that moringa leaf extract inhibits renal P-glycoprotein transport activity. So far, this reaction has not been reported in humans.

Theoretically, moringa might have additive effects when used with antidiabetes drugs; however, research is conflicting.
Animal research shows that moringa can lower blood glucose levels. However, research in humans has not shown consistent blood glucose lowering effects.

Theoretically, moringa might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that moringa extract induces CYP1A2 enzymes.

Moringa leaf is unlikely to have a clinically significant interaction with nevirapine.
Nevirapine is partially metabolized by cytochrome P450 3A4 (CYP3A4). In vitro evidence suggests that moringa inhibits CYP3A4. However, a pharmacokinetic study in patients with HIV shows no change in nevirapine pharmacokinetics when administered concomitantly with moringa leaf powder 1.85 grams daily for 14 days.

Theoretically, schisandra might increase the levels and clinical effects of cyclophosphamide.
In vitro research shows that schisandra increases the concentration of cyclophosphamide, likely through inhibition of cytochrome P450 3A4. After multiple doses of the schisandra constituents schisandrin A and schisantherin A, the maximum concentration of cyclophosphamide was increased by 7% and 75%, respectively, while the overall exposure to cyclophosphamide was increased by 29% and 301%, respectively.

Schisandra can increase the levels and clinical effects of cyclosporine.
A small observational study in children with aplastic anemia found that taking schisandra with cyclosporine increased cyclosporine trough levels by 93% without increasing the risk of adverse events. However, the dose of cyclosporine was reduced in 9% of children to maintain appropriate cyclosporine blood concentrations.

Theoretically, schisandra might increase the levels and clinical effects of CYP2C19 substrates.
In vitro research shows that schisandra inhibits CYP2C19, and animal research shows that schisandra increases the concentration of voriconazole, a CYP2C19 substrate. Theoretically, schisandra may also inhibit the metabolism of other CYP2C19 substrates. This effect has not been reported in humans.

Theoretically, schisandra might decrease the levels and clinical effects of CYP2C9 substrates.
In vitro and animal research suggests that schisandra induces CYP2C9 enzymes. This effect has not been reported in humans.

Schisandra can increase the levels and clinical effects of drugs metabolized by CYP3A4.
Most clinical and laboratory research shows that schisandra, administered either as a single dose or up to twice daily for 14 days, inhibits CYP3A4 and increases the concentration of CYP3A4 substrates such as cyclophosphamide, midazolam, tacrolimus, and talinolol. Although one in vitro and animal study shows that schisandra may induce CYP3A4 metabolism, this effect appears to be overpowered by schisandra's CYP3A4 inhibitory activity and has not been reported in humans.

Schisandra can increase the levels and clinical effects of midazolam.
A small pharmacokinetic study in healthy adults shows that taking schisandra extract (Hezheng Pharmaceutical Co.) containing deoxyschizandrin 33.75 mg twice daily for 8 days and a single dose of midazolam 15 mg on day 8 increases the overall exposure to midazolam by about 119%, increases the peak plasma level of midazolam by 86%, and decreases midazolam clearance by about 52%. This effect has been attributed to inhibition of CYP3A4 by schisandra.

Schisandra might increase the levels and clinical effects of P-glycoprotein substrates.
In vitro research shows that schisandra extracts and constituents such as schisandrin B inhibit P-glycoprotein mediated efflux in intestinal cells and in P-glycoprotein over-expressing cell lines. Additionally, a small clinical study shows that schisandra increases the peak concentration and overall exposure to talinolol, a P-glycoprotein probe substrate. Theoretically, schisandra might inhibit the efflux of other P-glycoprotein substrates.

Schisandra can increase the levels and clinical effects of sirolimus.
A small pharmacokinetic study in healthy volunteers shows that taking 3 capsules of schisandra (Hezheng Pharmaceutical Company) containing a total of 33.75 mg deoxyschizandrin twice daily for 13 days and then taking a single dose of sirolimus 2 mg increases the overall exposure and peak level of sirolimus by two-fold. This effect is thought to be due to inhibition of cytochrome P450 3A4 by schisandra, as well as possible inhibition of the P-glycoprotein drug transporter.

Schisandra can increase the levels and clinical effects of tacrolimus.
Clinical research in healthy children and adults, transplant patients, and patients with nephrotic syndrome and various rheumatic immunologic disorders shows that taking schisandra with tacrolimus increases tacrolimus peak levels by 183% to 268%, prolongs or delays time to peak tacrolimus concentrations, increases overall exposure to tacrolimus by 126% to 343%, and decreases tacrolimus clearance by 19% to 73%. This effect is thought to be due to inhibition of P-glycoprotein drug transporter and CYP3A4 and CYP3A5 by schisandra. Some clinical and observational studies suggest that schisandra increases tacrolimus levels similarly in both expressors and non-expressors of CYP3A5, while other studies suggest it does so to a greater degree in CYP3A5 expressors than non-expressors. Animal research suggests that the greatest increase in tacrolimus levels occurs when schisandra is taken either concomitantly or up to 2 hours before tacrolimus, and clinical and observational research in humans suggests that schisandra may increase whole blood levels of tacrolimus and decrease clearance of tacrolimus in a dose-dependent manner.

Schisandra can increase the levels and clinical effects of talinolol.
A small pharmacokinetic study in healthy volunteers shows that taking schisandra extract 300 mg twice daily for 14 days with a single dose of talinolol 100 mg on day 14 increases the peak talinolol level by 51% and the overall exposure to talinolol by 47%. This effect is thought to be due to the possible inhibition of cytochrome P450 3A4 and P-glycoprotein by schisandra. tly.

Theoretically, schisandra might increase the levels and clinical effects of voriconazole.
Animal research shows that oral schisandra given daily for 1 or 14 days increases levels of intravenously administered voriconazole, a cytochrome P450 (CYP) 2C19 substrate. This effect is thought to be due to inhibition of CYP2C19 by schisandra. However, this interaction has not been reported in humans.

Theoretically, schisandra might decrease the levels and clinical effects of warfarin.
Animal research suggests that oral schisandra extract, given daily for 6 days, reduces levels of intravenously administered warfarin. This effect might be due to the induction of cytochrome P450 (CYP) 2C9 metabolism by schisandra. However, this interaction has not been reported in humans.

Theoretically, alfalfa might reduce the anticoagulant activity of warfarin.
Alfalfa contains a large amount of vitamin K. This could theoretically interfere with the activity of warfarin.

Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research suggests that alfalfa decreases blood sugar in diabetic mice. Also, in one case report, a diabetic patient experienced hypoglycemia after consuming alfalfa extract. Monitor blood glucose levels closely. Dose adjustments might be necessary.

Theoretically, alfalfa might interfere with the activity of contraceptive drugs.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.

Theoretically, alfalfa might interfere with hormone therapy.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.

Theoretically, alfalfa might decrease the efficacy of immunosuppressive therapy.
In vitro research and human case reports suggest that alfalfa may have immunostimulant effects.

Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Animal research suggests that excessive doses of alfalfa may increase photosensitivity, possibly due to its chlorophyll content. It is unclear if this effect would be clinically relevant in humans.

Theoretically, taking dandelion root along with anticoagulant or antiplatelet drugs might increase the risk of bruising and bleeding.
In vitro research suggests that dandelion root inhibits platelet aggregation.

Theoretically, dandelion might increase the risk for hypoglycemia when used with antidiabetes drugs.
Laboratory research suggests that dandelion extract may have moderate alpha-glucosidase inhibitor activity and might also increase insulin secretion. Also, in a case report, a 58-year-old woman with type 2 diabetes who was being treated with insulin developed hypoglycemia 2 weeks after beginning to eat salads containing dandelion.

Theoretically, dandelion might increase levels of drugs metabolized by CYP1A2.
Laboratory research suggests that dandelion might inhibit CYP1A2. So far, this interaction has not been reported in humans. However, until more is known, watch for an increase in the levels of drugs metabolized by CYP1A2 in patients taking dandelion.

Theoretically, dandelion might increase the clearance of drugs that are UDP-glucuronosyltransferase substrates.
There is some preliminary evidence that dandelion might induce UDP-glucuronosyltransferase, a phase II enzyme.

Theoretically, through diuretic effects, dandelion might reduce excretion and increase levels of lithium.
Animal research suggests that dandelion has diuretic properties. As diuretics can increase serum lithium levels, the dose of lithium might need to be decreased when taken with dandelion.

Theoretically, dandelion might increase the risk of hyperkalemia when taken with potassium-sparing diuretics.
Dandelion contains significant amounts of potassium.

Theoretically, dandelion might lower fluoroquinolone levels.
Animal research shows that dandelion reduces absorption of ciprofloxacin and can lower levels by 73%. However, this effect has not been reported in humans.

Theoretically, chlorella might have additive effects with photosensitizing drugs.
Chlorella has been reported to cause photosensitization. In five case reports, patients who had ingested chlorella exhibited swelling followed by erythematopurpuric lesions on sun-exposed areas of the body. Theoretically, concomitant use with photosensitizing drugs may exacerbate effects.

Theoretically, chlorella might reduce the clinical effects of warfarin.
Chlorella contains significant amounts of vitamin K. There is at least one case report of warfarin therapy becoming sub-therapeutic after initiation of chlorella supplements.

Theoretically, spirulina blue-green algae might increase the risk of bleeding if used with other anticoagulant or antiplatelet drugs. However, this is unlikely.
Spirulina blue-green algae have shown antiplatelet and anticoagulant effects in vitro. However, one preliminary study in 24 patients receiving spirulina blue-green algae 2.3 grams daily for 2 weeks showed no effect on platelet activation or measures of clotting time.

Theoretically, taking blue-green algae with antidiabetes drugs might increase the risk of hypoglycemia.
Human research shows that spirulina blue-green algae can have hypoglycemic effects in patients with diabetes, at least some of whom were using antidiabetes drugs. However, blue-green algae does not seem to improve glycated hemoglobin (HbA1c) levels in patients with diabetes. A meta-analysis of animal studies also suggests that spirulina blue-green algae have hypoglycemic effects.

Theoretically, concurrent use of blue-green algae might interfere with immunosuppressive therapy.
Blue-green algae have been shown to stimulate the immune system.

Theoretically, cordyceps may increase the risk of bleeding when used with antiplatelet or anticoagulant drugs.
In vitro and animal research suggests that cordyceps extract inhibits platelet aggregation and function. However, this interaction has not been reported in humans.

Theoretically, concurrent use of cordyceps might interfere with immunosuppressive therapy.
Animal and in vitro research suggests that cordyceps stimulates the immune system. However, limited clinical research suggests that taking cordyceps may lower the necessary therapeutic dose of the immunosuppressant cyclosporine, which suggests that cordyceps may have an immunosuppressive effect.

Theoretically, concurrent use of cordyceps and testosterone might have additive effects.
Animal research suggests that cordyceps can increase testosterone levels. The clinical significance of this finding is unclear.

Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.

Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption. In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely. Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.

Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin. In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells. More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.

Vitamin C might increase blood levels of estrogens.
Increases in plasma estrogen levels of up to 55% occur under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products. It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall. When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements. Monitor these patients for estrogen-related side effects.

Theoretically, vitamin C might decrease levels of fluphenazine.
In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started. The mechanism is not known, and there is no further data to confirm this interaction.

Vitamin C can modestly reduce indinavir levels.
One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown.

Vitamin C can increase levothyroxine absorption.
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH.

High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption. There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time. Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant. However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.

High-dose vitamin C might slightly prolong the clearance of acetaminophen.
A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases. This effect is not likely to be clinically significant.

Acidification of the urine by vitamin C might increase aspirin levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction is not clinically significant.

Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.

Acidification of the urine by vitamin C might increase salsalate levels.
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels. However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion, suggesting this interaction probably is not clinically significant.

Theoretically, a high intake of dietary sodium might reduce the effectiveness of antihypertensive drugs.
High intake of dietary sodium can increase systolic and diastolic blood pressure. Also, high intake of sodium may necessitate increased use of antihypertensive medications to achieve blood pressure control in some patients, such as those with chronic kidney disease.

Concomitant use of mineralocorticoids and some glucocorticoids with sodium supplements might increase the risk of hypernatremia.
Mineralocorticoids and some glucocorticoids (corticosteroids) cause sodium retention. This effect is dose-related and depends on mineralocorticoid potency. It is most common with hydrocortisone, cortisone, and fludrocortisone, followed by prednisone and prednisolone.

Concomitant use of didanosine with additional sodium from dietary or supplemental sources may increase the risk of hypernatremia.
Didanosine formulations contain a significant amount of sodium.

Altering dietary intake of sodium might alter the levels and clinical effects of lithium.
High sodium intake can reduce plasma concentrations of lithium by increasing lithium excretion. Reducing sodium intake can significantly increase plasma concentrations of lithium and cause lithium toxicity in patients being treated with lithium carbonate. Stabilizing sodium intake is shown to reduce the percentage of patients with lithium level fluctuations above 0.8 mEq/L. Patients taking lithium should avoid significant alterations in their dietary intake of sodium.

Theoretically, concomitant use of sodium phosphate with sodium supplements might increase the risk of hypernatremia.
Use of high doses (> 45 mL in 24 hours) of sodium phosphate, such as those used for bowel cleansing before surgery, can lead to serious electrolyte disturbances, including hypernatremia. The risk of hypernatremia is highest in the elderly and people with other risk factors for electrolyte disturbances.

Concomitant use of sodium-containing drugs with additional sodium from dietary or supplemental sources may increase the risk of hypernatremia and long-term sodium-related complications.
The Chronic Disease Risk Reduction (CDRR) intake level of 2.3 grams of sodium daily indicates the intake at which it is believed that chronic disease risk increases for the apparently healthy population. Some medications contain high quantities of sodium. When used in conjunction with sodium supplements or high-sodium diets, the CDRR may be exceeded. Additionally, concomitant use may increase the risk for hypernatremia; this risk is highest in the elderly and people with other risk factors for electrolyte disturbances.

Theoretically, concomitant use of tolvaptan with sodium might increase the risk of hypernatremia.
Tolvaptan is a vasopressin receptor 2 antagonist that is used to increase sodium levels in patients with hyponatremia. Patients taking tolvaptan should use caution with the use of sodium salts such as sodium chloride.

Co-administration of intravenous calcium and ceftriaxone can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys.
Avoid administering intravenous calcium in any form, such as parenteral nutrition or Lactated Ringers, within 48 hours of intravenous ceftriaxone. Case reports in neonates show that administering intravenous ceftriaxone and calcium can result in precipitation of a ceftriaxone-calcium salt in the lungs and kidneys. In several cases, neonates have died as a result of this interaction. So far there are no reports in adults; however, there is still concern that this interaction might occur in adults.

Calcium seems to reduce levels of dolutegravir.
Advise patients to take dolutegravir either 2 hours before or 6 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium carbonate 1200 mg concomitantly with dolutegravir 50 mg reduces plasma levels of dolutegravir by almost 40%. Calcium appears to decrease levels of dolutegravir through chelation.

Calcium seems to reduce levels of elvitegravir.
Advise patients to take elvitegravir either 2 hours before or 2 hours after taking calcium supplements. Pharmacokinetic research suggests that taking calcium along with elvitegravir can reduce blood levels of elvitegravir through chelation.

Calcium citrate might increase aluminum absorption and toxicity. Other types of calcium do not increase aluminum absorption.
Calcium citrate can increase the absorption of aluminum when taken with aluminum hydroxide. The increase in aluminum levels may become toxic, particularly in individuals with kidney disease. However, the effect of calcium citrate on aluminum absorption is due to the citrate anion rather than calcium cation. Calcium acetate does not appear to increase aluminum absorption.

Calcium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide and calcium can be taken together if taken with food. However, if taken on an empty stomach, bictegravir/emtricitabine/tenofovir alafenamide should not be taken with, or 2 hours after, calcium containing products.

Calcium reduces the absorption of bisphosphonates.
Advise patients to take bisphosphonates at least 30 minutes before calcium, but preferably at a different time of day. Calcium supplements decrease absorption of bisphosphonates.

Taking calcipotriene with calcium might increase the risk for hypercalcemia.
Calcipotriene is a vitamin D analog used topically for psoriasis. It can be absorbed in sufficient amounts to cause systemic effects, including hypercalcemia. Theoretically, combining calcipotriene with calcium supplements might increase the risk of hypercalcemia.

Using intravenous calcium with digoxin might increase the risk of fatal cardiac arrhythmias.
Hypercalcemia increases the risk of fatal cardiac arrhythmias with digoxin. However, one retrospective analysis of clinical data suggests that intravenous calcium does not increase the risk of dysrhythmias or mortality in patients receiving digoxin.

Theoretically, calcium may reduce the therapeutic effects of diltiazem.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, calcium might increase this risk of hypercalcemia and reduce the effectiveness of diltiazem.

Calcium seems to reduce the absorption and effectiveness of levothyroxine.
Advise patients to take levothyroxine and calcium supplements at least 4 hours apart. Calcium reduces levothyroxine absorption, probably by forming insoluble complexes. Calcium carbonate supplements reduce effectiveness of levothyroxine in patients with hypothyroidism.

Theoretically, concomitant use of calcium and lithium may increase this risk of hypercalcemia.
Clinical research suggests that long-term use of lithium may cause hypercalcemia in 10% to 60% of patients. Theoretically, concomitant use of lithium and calcium supplements may further increase this risk.

Calcium seems to reduce the absorption of quinolone antibiotics.
Advise patients to take oral quinolones at least 2 hours before or 4-6 hours after calcium supplements or calcium-fortified foods. Taking calcium at the same time as oral quinolones can reduce quinolone absorption. Calcium binds to quinolones in the gut.

Calcium may reduce levels of raltegravir.
Pharmacokinetic research shows that taking a single dose of calcium carbonate 3000 mg along with raltegravir 400 mg twice daily modestly decreases the mean area under the curve of raltegravir, but the decrease does not necessitate a dose adjustment of raltegravir. However, a case of elevated HIV-1 RNA levels and documented resistance to raltegravir has been reported for a patient taking calcium carbonate 1 gram three times daily plus vitamin D3 (cholecalciferol) 400 IU three times daily in combination with raltegravir 400 mg twice daily for 11 months. It is thought that calcium reduced raltegravir levels by chelation, leading to treatment failure.

Calcium seems to reduce the absorption of sotalol.
Advise patients to separate doses by at least 2 hours before or 4-6 hours after calcium. Calcium appears to reduce the absorption of sotalol, probably by forming insoluble complexes.

Calcium seems to reduce the absorption of tetracycline antibiotics.
Advise patients to take oral tetracyclines at least 2 hours before, or 4-6 hours after calcium supplements. Taking calcium at the same time as oral tetracyclines can reduce tetracycline absorption. Calcium binds to tetracyclines in the gut.

Taking calcium along with thiazides might increase the risk of hypercalcemia and renal failure.
Thiazides reduce calcium excretion by the kidneys. Using thiazides along with moderately large amounts of calcium carbonate increases the risk of milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). Patients may need to have their serum calcium levels and/or parathyroid function monitored regularly.

Theoretically, calcium may reduce the therapeutic effects of verapamil.
Hypercalcemia can reduce the effectiveness of verapamil in atrial fibrillation. Theoretically, use of calcium supplements may increase this risk of hypercalcemia and reduce the effectiveness of verapamil.

Intravenous calcium may decrease the effects of calcium channel blockers; oral calcium is unlikely to have this effect.
Intravenous calcium is used to decrease the effects of calcium channel blockers in the management of overdose. Intravenous calcium gluconate has been used before intravenous verapamil (Isoptin) to prevent or reduce the hypotensive effects without affecting the antiarrhythmic effects. But there is no evidence that dietary or supplemental calcium when taken orally interacts with calcium channel blockers.

Bromelain may have antiplatelet effects and may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
There is one case report of a patient experiencing minor bruising while taking bromelain with naproxen. Bromelain is thought to have antiplatelet activity. Whether this interaction is of concern with topical bromelain is unclear. Interference with coagulation of burn wounds has been reported in a patient receiving bromelain-based enzymatic debridement. However, observational research has found that topical bromelain debridement is not associated with increases or decreases in laboratory markers of coagulation when compared with surgical debridement.

Theoretically, bromelain might increase levels of tetracycline antibiotics.
Laboratory research suggests that bromelain might increase the absorption of tetracycline antibiotics. However, a study in healthy adults reported no difference in tetracycline plasma levels when a 500 mg dose was taken with or without bromelain 80 mg.

Combining prickly pear cactus with antidiabetes drugs might increase the risk of hypoglycemia.
Case reports show that combining prickly pear cactus with antidiabetes drugs such as chlorpropamide, glyburide, glipizide, and metformin can increase the risk of hypoglycemia in patients with type 2 diabetes. Advise patients to monitor glucose levels closely. Dose adjustments may be necessary.

Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.
Consuming oats can decrease blood glucose in patients with diabetes. In those who require insulin, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.

Concomitant use of oats and insulin might increase the risk of hypoglycemia.
In patients with insulin-dependent type 2 diabetes, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.

Iron might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption when taken in a fasting state.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide and iron can be taken together if taken with food. However, if taken on an empty stomach, bictegravir/emtricitabine/tenofovir alafenamide should not be taken with, or 2 hours after, iron containing products.

Iron reduces the absorption of bisphosphonates.
Advise patients that doses of bisphosphonates should be separated by at least two hours from doses of all other medications, including supplements such as iron. Divalent cations, including iron, can decrease absorption of bisphosphonates by forming insoluble complexes in the gastrointestinal tract.

Administration of intravenous iron within one month of denosumab administration might increase the risk of severe hypophosphatemia and hypocalcemia.
A case of severe hypocalcemia (albumin corrected calcium 6.88 mg/dL, ionized calcium 3.68 mg/dL) and hypophosphatemia (<0.5 mg/dL) with respiratory acidosis, QT interval prolongation, and nonsustained ventricular tachycardia was reported in a 76-year-old male who had received an iron polymaltose infusion within 2 weeks of a subcutaneous injection of denosumab. Serum parathyroid hormone was also elevated (348 pg/mL). Subsequent iron infusions with iron polymaltose and ferric carboxymaltose were followed by transient hypophosphatemia, but without hypocalcemia. Additionally, a literature review describes 6 additional cases of hypophosphatemia and hypocalcemia in patients 52-92 years of age who had been administered intravenous iron as either ferric carboxymaltose or iron polymaltose and subcutaneous denosumab within 1-4 weeks of each other.

Iron might decrease dolutegravir levels by reducing its absorption.
Advise patients to take dolutegravir at least 2 hours before or 6 hours after taking iron. Pharmacokinetic research shows that iron can decrease the absorption of dolutegravir from the gastrointestinal tract through chelation. When taken under fasting conditions, a single dose of ferrous fumarate 324 mg orally along with dolutegravir 50 mg reduces overall exposure to dolutegravir by 54%.

Theoretically, taking iron along with integrase inhibitors might decrease the levels and clinical effects of these drugs.
Iron is a divalent cation. There is concern that iron may decrease the absorption of integrase inhibitors from the gastrointestinal tract through chelation. One pharmacokinetic study shows that iron can decrease blood levels of the specific integrase inhibitor dolutegravir through chelation. Also, other pharmacokinetic research shows that other divalent cations such as calcium can decrease the absorption and levels of some integrase inhibitors through chelation.

Iron might decrease levodopa levels by reducing its absorption.
Advise patients to separate doses of levodopa and iron as much as possible. There is some evidence in healthy people that iron forms chelates with levodopa, reducing the amount of levodopa absorbed by around 50%. The clinical significance of this hasn't been determined.

Iron might decrease levothyroxine levels by reducing its absorption.
Advise patients to separate levothyroxine and iron doses by at least 2 hours. Iron can decrease the absorption and efficacy of levothyroxine by forming insoluble complexes in the gastrointestinal tract.

Iron might decrease methyldopa levels by reducing its absorption.
Advise patients to separate methyldopa and iron doses by at least 2 hours. Iron can decrease the absorption of methyldopa from the gastrointestinal tract through chelation, resulting in increases in blood pressure.

Theoretically, iron might decrease mycophenolate mofetil levels by reducing its absorption.
Advise patients to take iron 4-6 hours before, or 2 hours after, mycophenolate mofetil. It has been suggested that a decrease of absorption is possible, probably by forming nonabsorbable chelates. However, mycophenolate pharmacokinetics are not affected by iron supplementation in available clinical research.

Iron might decrease penicillamine levels by reducing its absorption.
Advise patients to separate penicillamine and iron doses by at least 2 hours. Oral iron supplements can reduce absorption of penicillamine by 30% to 70%, probably due to chelate formation. In people with Wilson's disease, this interaction has led to reduced efficacy of penicillamine.

Iron might decrease levels of quinolone antibiotics by reducing their absorption.
Advise patients to separate quinolone antibiotics and iron doses by at least 2 hours. Iron decreases the absorption of quinolones due to formation of insoluble complexes in the gastrointestinal tract.

Iron might decrease levels of tetracycline antibiotics by reducing their absorption.
Advise patients to take iron at least 2 hours before or 4 hours after tetracycline antibiotics. Concomitant use can decrease absorption of tetracycline antibiotics from the gastrointestinal tract by 50% to 90%.