Herb & supplement monograph

Magnesium Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Magnesium interacts with medications. The heart of this page is the interaction list — every drug Magnesium is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Magnesium is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

Check Magnesium against your medication

Add one medication

✓ Supplement

Magnesium

1 Your medication

Start typing any prescription or over-the-counter drug name.

Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Magnesium Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the risk of a clinically significant Magnesium drug interaction is moderate for many people, mostly because magnesium can change how well certain medications are absorbed. Most of the listed interactions are rated moderate, over a hundred are minor, and only a handful are considered major.

Interactions deserving the most attention

The best-documented concern is levodopa/carbidopa for Parkinson's disease, where human studies show magnesium can sharply cut the amount of medication the body absorbs. Magnesium can also increase absorption of sulfonylureas used for diabetes, raising the chance of low blood sugar. It can bind to quinolone and tetracycline antibiotics in the gut, making them less effective, and it may modestly reduce digoxin levels.

What the rest of the list means

Most of this long list reflects effects on absorption in the digestive tract rather than dangerous reactions, and many of these interactions are commonly managed with simple dose spacing rather than avoiding the combination. Other entries rest on lab or animal research, and some predicted effects, such as increased bleeding with blood thinners, have not held up consistently in human studies.

Check your medications against Magnesium

Based on HelloPharmacist’s Magnesium interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Magnesium

295 medications have a known interaction with Magnesium, graded by severity. Select any drug for the full evidence-based detail.

6 major interactions. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with Magnesium.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Magnesium using our pharmacist-reviewed interaction data.

AI summaries are generated from our Magnesium interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Magnesium combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Magnesium affects

Every type of medication (drug category) Magnesium is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 15 drug categories Magnesium interacts with

Levodopa/carbidopa (sinemet)Aminoglycoside AntibioticsAntacidsBictegravir/emtricitabine/tenofovir Alafenamide (biktarvy)BisphosphonatesCalcium Channel BlockersDigoxinPotassium-sparing DiureticsQuinolone AntibioticsSkeletal Muscle RelaxantsSulfonylureasTetracycline AntibioticsAnticoagulant/antiplatelet DrugsGabapentin (neurontin)Sevelamer (renagel, Renvela)

Levodopa/Carbidopa (Sinemet)

Magnesium can reduce the bioavailability of levodopa/carbidopa.
Clinical research in healthy volunteers shows that taking magnesium oxide 1000 mg with levodopa 100 mg/carbidopa 10 mg reduces the area under the curve (AUC) of levodopa by 35% and of carbidopa by 81%. In vitro and animal research shows that magnesium produces an alkaline environment in the digestive tract, which might lead to degradation and reduced bioavailability of levodopa/carbidopa.

Likelihood Probable Evidence B

Aminoglycoside Antibiotics

Concomitant use of aminoglycoside antibiotics and magnesium can increase the risk for neuromuscular weakness.
Both aminoglycosides and magnesium reduce presynaptic acetylcholine release, which can lead to neuromuscular blockade and possible paralysis. This is most likely to occur with high doses of magnesium given intravenously.

Likelihood Possible Evidence D

Antacids

Use of acid reducers may reduce the laxative effect of magnesium oxide.
A retrospective analysis shows that, in the presence of H2 receptor antagonists (H2RAs) or proton pump inhibitors (PPIs), a higher dose of magnesium oxide is needed for a laxative effect. This may also occur with antacids. Under acidic conditions, magnesium oxide is converted to magnesium chloride and then to magnesium bicarbonate, which has an osmotic laxative effect. By reducing acidity, antacids may reduce the conversion of magnesium oxide to the active bicarbonate salt.

Likelihood Possible Evidence D

Bictegravir/Emtricitabine/Tenofovir Alafenamide (Biktarvy)

Magnesium might decrease levels of bictegravir/emtricitabine/tenofovir alafenamide by reducing its absorption.
Advise patients that bictegravir/emtricitabine/tenofovir alafenamide should be taken at least 2 hours before or 6 hours after magnesium containing products.

Likelihood Probable Evidence D

Bisphosphonates

Magnesium can decrease absorption of bisphosphonates.
Cations, including magnesium, can decrease bisphosphonate absorption. Advise patients to separate doses of magnesium and these drugs by at least 2 hours.

Likelihood Probable Evidence B

Calcium Channel Blockers

Magnesium can have additive effects with calcium channel blockers, although evidence is conflicting.
Magnesium inhibits calcium entry into smooth muscle cells and may therefore have additive effects with calcium channel blockers. Severe hypotension and neuromuscular blockades may occur when nifedipine is used with intravenous magnesium, although some contradictory evidence suggests that concurrent use of magnesium with nifedipine does not increase the risk of neuromuscular weakness. High doses of magnesium could theoretically have additive effects with other calcium channel blockers.

Likelihood Possible Evidence D

Digoxin

Magnesium salts may reduce absorption of digoxin.
Clinical evidence suggests that treatment with oral magnesium hydroxide or magnesium trisilicate reduces absorption of digoxin from the intestines. This may reduce the blood levels of digoxin and decrease its therapeutic effects.

Likelihood Possible Evidence B

Potassium-Sparing Diuretics

Potassium-sparing diuretics decrease excretion of magnesium, possibly increasing magnesium levels.
Potassium-sparing diuretics also have magnesium-sparing properties, which can counteract the magnesium losses associated with loop and thiazide diuretics. Theoretically, increased magnesium levels could result from concomitant use of potassium-sparing diuretics and magnesium supplements.

Likelihood Probable Evidence D

Quinolone Antibiotics

Magnesium decreases absorption of quinolones.
Magnesium can form insoluble complexes with quinolones and decrease their absorption. Advise patients to take these drugs at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Probable Evidence D

Skeletal Muscle Relaxants

Parenteral magnesium alters the pharmacokinetics of skeletal muscle relaxants, increasing their effects and accelerating the onset of effect.
Parenteral magnesium shortens the time to onset of skeletal muscle relaxants by about 1 minute and prolongs the duration of action by about 2 minutes. Magnesium potentiates the effects of skeletal muscle relaxants by decreasing calcium-mediated release of acetylcholine from presynaptic nerve terminals, reducing postsynaptic sensitivity to acetylcholine, and having a direct effect on the membrane potential of myocytes. Magnesium also has vasodilatory actions and increases cardiac output, allowing a greater amount of muscle relaxant to reach the motor end plate. A clinical study found that low-dose rocuronium (0.45 mg/kg), when given after administration of magnesium 30 mg/kg over 10 minutes, has an accelerated onset of effect, which matches the onset of effect seen with a full-dose rocuronium regimen (0.6 mg/kg). In another clinical study, onset times for rocuronium doses of 0.3, 0.6, and 1.2 mg/kg were 86, 76, and 50 seconds, respectively, when given alone, but were reduced to 66, 44, and 38 seconds, respectively, when the doses were given after a 15-minute infusion of magnesium sulfate 60 mg/kg. Giving intraoperative intravenous magnesium sulfate, 50 mg/kg loading dose followed by 15 mg/kg/hour, reduces the onset time of rocuronium, enhances its clinical effects, reduces the dose of intraoperative opiates, and prolongs the spontaneous recovery time. It does not affect the activity of subsequently administered neostigmine.

Likelihood Probable Evidence A

Sulfonylureas

Magnesium increases the systemic absorption of sulfonylureas, increasing their effects and side effects.
Clinical research shows that administration of magnesium hydroxide with glyburide increases glyburide absorption, increases maximal insulin response by 35-fold, and increases the risk of hypoglycemia, when compared with glyburide alone. A similar interaction occurs between magnesium hydroxide and glipizide. The mechanism of this effect appears to be related to the elevation of gastrointestinal pH by magnesium-based antacids, increasing solubility and enhancing absorption of sulfonylureas.

Likelihood Probable Evidence B

Tetracycline Antibiotics

Magnesium decreases absorption of tetracyclines.
Magnesium can form insoluble complexes with tetracyclines in the gut and decrease their absorption and antibacterial activity. Advise patients to take these drugs 1 hour before or 2 hours after magnesium supplements.

Likelihood Probable Evidence D

Anticoagulant/Antiplatelet Drugs

Theoretically, magnesium may have antiplatelet effects, but the evidence is conflicting.
In vitro evidence shows that magnesium sulfate inhibits platelet aggregation, even at low concentrations. Some preliminary clinical evidence shows that infusion of magnesium sulfate increases bleeding time by 48% and reduces platelet activity. However, other clinical research shows that magnesium does not affect platelet aggregation, although inhibition of platelet-dependent thrombosis can occur.

Likelihood Unlikely Evidence B

Gabapentin (Neurontin)

Gabapentin absorption can be decreased by magnesium.
Clinical research shows that giving magnesium oxide orally along with gabapentin decreases the maximum plasma concentration of gabapentin by 33%, time to maximum concentration by 36%, and area under the curve by 43%. Advise patients to take gabapentin at least 2 hours before, or 4 to 6 hours after, magnesium supplements.

Likelihood Unlikely Evidence B

Sevelamer (Renagel, Renvela)

Sevelamer may increase serum magnesium levels.
In patients on hemodialysis, sevelamer use was associated with a 0.28 mg/dL increase in serum magnesium. The mechanism of this interaction remains unclear.

Likelihood Possible Evidence B

Monograph

Magnesium: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Magnesium is an essential mineral your body needs for muscles, nerves, blood pressure, and many other functions, and supplements are useful for preventing or correcting deficiency. Some other uses, like easing constipation or preventing migraines, have reasonable support, while uses for sleep and anxiety are less proven. It is generally safe for most healthy people at recommended amounts, but talk to your pharmacist or doctor before starting, especially if you have kidney problems.

Part used: Mineral (not a plant part)
Common forms: Tablets, capsules, powders, liquids, gummies, and topical Epsom salts; common forms include magnesium citrate, glycinate, oxide, chloride, malate, and aspartate

People commonly use it for

Preventing or treating magnesium deficiency
Constipation
Muscle cramps
Sleep support
Anxiety and stress
Migraine prevention

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallLikely safe

Generally safe for healthy adults when taken at recommended amounts from food and supplements.

PregnancyLikely Safe

When used orally and appropriately. Magnesium is safe for those pregnant and breast-feeding when used in doses below the tolerable upper intake level...

Read the full pregnancy detail

BreastfeedingLikely Safe

When used orally and appropriately. Magnesium is safe for those pregnant and breast-feeding when used in doses below the tolerable upper intake level...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Magnesium is a mineral your body needs to work properly. It helps your muscles contract and relax, lets your nerves send signals, supports a steady heartbeat, and helps control blood sugar and blood pressure. Your body cannot make magnesium, so you must get it from food or supplements.

Many everyday foods are rich in magnesium, including leafy green vegetables, nuts, seeds, beans, whole grains, and dark chocolate. Most people get some magnesium from their diet, but certain people may fall short.

Magnesium supplements come in many forms, such as magnesium citrate, glycinate, oxide, chloride, malate, and aspartate. Epsom salt (magnesium sulfate) is often dissolved in bath water. People take magnesium to prevent deficiency and for a range of other reasons, from constipation relief to sleep and muscle cramps.

How it works

Magnesium acts as a helper, called a cofactor, in hundreds of chemical reactions in the body. It is involved in making energy, building proteins and DNA, and keeping muscle and nerve cells working normally.

It helps balance other minerals like calcium and potassium, which is part of why it affects muscle relaxation, heart rhythm, and blood pressure. When taken in larger amounts that are not absorbed, magnesium pulls water into the gut, which softens stool and produces a laxative effect.

For uses like sleep and anxiety, the proposed mechanisms involve magnesium's effects on nerve signaling and stress hormones. These ideas come largely from laboratory and early research, and they do not guarantee a noticeable benefit for everyone.

Effectiveness

Does Magnesium work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 87 uses evaluated

5 Effective 3 Likely effective 10 Possibly effective 13 Leans ineffective 56 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

Effective Bowel preparation