Does My Medication Cause Nutrient Depletion?
Some prescription and over-the-counter medications can lower your levels of important vitamins and minerals over time. Search your medication below to see what it may deplete — with evidence ratings and what to discuss with your pharmacist.
Potential nutrient considerations for your selected medication
1 medication checked · 9 nutrients with reported associations. These are talking points for your care team — not a diagnosis.
BIOTIN
Insignificant DepletionANTIBIOTIC DRUGS
Interference with the normal gastrointestinal flora by antibiotics may reduce bacterial synthesis of biotin. Although some bacterially-synthesized biotin can be absorbed from the lower intestine, this appears to contribute less than 20% of a person's daily requirement for biotin. Therefore it's unlikely that antibiotics would contribute to biotin deficiency.
References (4)
- Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
- Grundy WE, Freed M, Johnson H.C., et al. The effect of phthalylsulfathiazole (sulfathalidine) on the excretion of B-vitamins by normal adults. Arch Biochem. 1947 Nov;15:187-94.
FOLIC ACID
Insignificant DepletionANTIBIOTIC DRUGS
Antibiotic therapy can disrupt the normal gastrointestinal (GI) flora, interfering with enterohepatic recirculation (reabsorption) of folic acid. The normal GI flora also synthesizes and consumes folic acid, which may also be disrupted by antibiotics. Folic acid synthesized by GI bacteria can be absorbed in the large intestine, but the amount synthesized and absorbed is variable. For instance, it can depend on dietary fiber intake and gastric pH; hypochlorhydria causes bacterial overgrowth and increased folate synthesis. In most people it's unlikely that a course of antibiotics will reduce folic acid levels significantly, and therefore supplements are unnecessary. For information on foods that are rich in folate, see our chart.
What Folic acid (folate) does & food sources
Folate is needed for cell division, red blood cell formation, and healthy fetal development.
Common food sources:
- Leafy green vegetables
- Beans, lentils, and peas
- Fortified grains and cereals
- Citrus fruits
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask your provider whether folate monitoring or supplementation is appropriate for you — this matters most before and during pregnancy, and with long-term use of certain seizure or arthritis medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Folate needs are individual. With some medications (for example, methotrexate), folic acid is often prescribed deliberately on a specific schedule — follow your prescriber's instructions rather than adding your own.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: High-dose folic acid can mask vitamin B12 deficiency, so the two are often evaluated together.
References (5)
- Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
- Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
- Russell RM, Krasinski SD, Samloff IM, et al. Folic acid malabsorption in atrophic gastritis: possible compensation by bacterial folate synthesis. Gastroenterology 1986;91:1476-82. PubMed
RIBOFLAVIN
Insignificant DepletionANTIBIOTIC DRUGS
Interference with the normal gastrointestinal flora by antibiotics may reduce bacterial synthesis of riboflavin. However, this synthesis doesn't seem to significantly contribute to the body's supply of riboflavin, which is primarily obtained from dietary sources. Riboflavin supplements aren't necessary during antibiotic therapy.
What Vitamin B2 (riboflavin) does & food sources
Riboflavin helps the body produce energy and process other B vitamins.
Common food sources:
- Dairy products and eggs
- Lean meats
- Fortified grains
- Green vegetables
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Deficiency is uncommon with a varied diet; ask your provider if you have persistent mouth-corner cracking, sore tongue, or unexplained fatigue on a long-term associated medication.
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Supplement considerations
Riboflavin is water-soluble and excess is excreted (it turns urine bright yellow — harmless).
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
References (3)
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
- McCormick DB. Riboflavin. In: Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999. pg.391-9.
THIAMINE
Insignificant DepletionANTIBIOTIC DRUGS
Interference with the normal gastrointestinal flora by antibiotics may reduce bacterial synthesis of thiamine. However, the majority of the daily thiamine requirement is obtained from the diet, rather than synthesis by the GI flora. Therefore this isn't likely to be clinically significant, and thiamine supplements aren't necessary.
What Vitamin B1 (thiamine) does & food sources
Thiamine helps convert food into energy and is essential for nerve and heart function.
Common food sources:
- Whole grains and fortified cereals
- Pork
- Beans and lentils
- Nuts and seeds
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask about thiamine if you take an associated medication (for example, a long-term loop diuretic in heart failure) and have symptoms like fatigue or worsening heart failure control — this is an area your care team can weigh.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Thiamine is water-soluble and generally low-risk, but supplementing to treat a suspected problem should still be clinician-guided so the real cause is not missed.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
References (1)
- Goldin BR, Lichtenstein AH, Gorbach SL. Nutritional and metabolic roles of intestinal flora. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th ed. Malvern, PA: Lea & Febiger, 1994.
VITAMIN B12
Insignificant DepletionANTIBIOTIC DRUGS
Disruption of the normal gastrointestinal (GI) flora may interrupt enterohepatic recirculation of vitamin B12 and increase fecal excretion. Vitamin B12 is also synthesized by the GI flora, but mainly in the colon where absorption is poor. The majority of bacterially-synthesized vitamin B12 is therefore excreted in the feces and does not significantly contribute to the body's store of vitamin B12. The effects of antibiotics on gastrointestinal bacteria are unlikely to have clinically significant effects on vitamin B12 levels. In people with bacterial overgrowth of the small bowel, antibiotics such as metronidazole (Flagyl) can actually improve vitamin B12 status. An increased bacterial load can bind significant amounts of vitamin B12 in the gut, preventing its absorption.
What Vitamin B12 does & food sources
Vitamin B12 supports red blood cell formation, nerve function, and DNA synthesis.
Common food sources:
- Meat, poultry, and fish
- Eggs and dairy products
- Fortified cereals and nutritional yeast
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
If you take an associated medication long-term, ask your healthcare provider whether checking a vitamin B12 level (sometimes with methylmalonic acid) is appropriate — especially if you notice fatigue, numbness, tingling, or memory changes.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
B12 status is easy to check and low levels are usually straightforward to address, so testing before supplementing is often the sensible order. High-dose folic acid can mask a B12 deficiency, which is one reason B12 and folate questions are best sorted out together with your provider.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: B12 deficiency can look like other conditions — do not self-diagnose from symptoms alone.
References (3)
- Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Goldin BR, Lichtenstein AH, Gorbach SL. Nutritional and metabolic roles of intestinal flora. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th ed. Malvern, PA: Lea & Febiger, 1994.
VITAMIN B6
Insignificant DepletionANTIBIOTIC DRUGS
Some sources suggest that destruction of the normal gastrointestinal flora by antibiotics can decrease production and plasma levels of vitamin B6. However, there is no evidence that the gastrointestinal flora is a significant source of vitamin B6 in humans. Supplementation with vitamin B6 is not necessary during antibiotic therapy. For information on foods that are rich in vitamin B6, see our chart.
What Vitamin B6 does & food sources
Vitamin B6 is involved in protein metabolism, neurotransmitter production, and red blood cell formation.
Common food sources:
- Poultry and fish
- Potatoes and starchy vegetables
- Bananas
- Fortified cereals
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
With some medications (for example, isoniazid), B6 is intentionally co-prescribed — follow your prescriber's plan. Otherwise, ask whether testing or supplementation is appropriate if you have symptoms like numbness or tingling.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Paradoxically, long-term high-dose B6 can itself cause nerve symptoms — this is a nutrient where more is definitely not better.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Avoid high-dose B6 without medical guidance; sustained high intakes can cause neuropathy.
References (3)
- Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Goldin BR, Lichtenstein AH, Gorbach SL. Nutritional and metabolic roles of intestinal flora. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease, 8th ed. Malvern, PA: Lea & Febiger, 1994.
NIACIN
Moderate DepletionISONIAZID
Isoniazid can cause a deficiency of pyridoxine, which is needed for conversion of tryptophan to niacin, resulting in a secondary niacin deficiency. Isoniazid also has structural similarities to niacin and might interfere with niacin's conversion to nicotinamide adenine dinucleotide (NAD). Pellagra can occur in people taking isoniazid chronically, especially if dietary niacin intake is low. It can be prevented or reversed with niacin or niacinamide supplements.
What Vitamin B3 (niacin) does & food sources
Niacin supports energy metabolism, skin health, and nervous system function.
Common food sources:
- Poultry, beef, and fish
- Peanuts and legumes
- Fortified grains
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Deficiency is rare in a typical diet. Discuss with your provider before using niacin as a supplement — at pharmacologic doses it behaves like a medication.
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Supplement considerations
High-dose niacin causes flushing and can affect the liver, blood sugar, and uric acid — it is not a casual supplement.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Treat high-dose niacin as a medication decision, not a nutrition one.
References (6)
- Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
- Ishii N, Nishihara Y. Pellagra encephalopathy among tuberculous patients: its relation to isoniazid therapy. J Neurol Neurosurg Psychiatry 1985;48:628-34. PubMed
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (2000). Washington, DC: National Academy Press, 2000. Available at: http://b
- Darvay A, Basarab T, McGregor JM, Russell-Jones R. Isoniazid induced pellagra despite pyridoxine supplementation. Clin Exp Dermatol 1999;24:167-9. PubMed
- Stratigos JD, Katsambas A. Pellagra: a still existing disease. Br J Dermatol 1977;96:99-106. PubMed
- Bender DA, Russell-Jones R. Isoniazid-induced pellagra despite vitamin B6 supplementation (letter). Lancet 1979;2:1125-6. PubMed
VITAMIN D
Moderate DepletionRIFAMPIN (Rifadin)
Rifampin increases hepatic metabolism of 25-hydroxy-vitamin D, reducing its plasma levels. This can contribute to osteomalacia after prolonged therapy (>1 year), especially if vitamin D intake is low. However, if isoniazid (INH, Nydrazid) is taken concurrently with rifampin there doesn't seem to be any change in vitamin D status. This may be because the enzyme-inducing effects on rifampin are canceled out by the enzyme-inhibiting effects of isoniazid. For information on foods that are rich in vitamin D, see our chart.
What Vitamin D does & food sources
Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health.
Common food sources:
- Fatty fish (salmon, mackerel)
- Fortified milk and cereals
- Egg yolks
- Sunlight exposure (the main natural source)
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
A 25-hydroxyvitamin D blood test is the standard way to assess status — ask whether it is appropriate if you take an associated medication long-term, have limited sun exposure, or have bone concerns.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin D dosing varies a lot between people; some medications change how vitamin D is processed. Your provider can target a dose to your level instead of guessing.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin D is fat-soluble and can accumulate — very high doses over time can cause harm, so follow a clinician-guided plan.
References (5)
- Williams SE, Wardman AG, Taylor GA, et al. Long term study of the effect of rifampicin and isoniazid on vitamin D metabolism. Tubercle 1985;66:49-54. PubMed
- Kovacs CS, Jones G, Yendt ER. Primary hyperparathyroidism masked by antituberculous therapy-induced vitamin D deficiency. Clin Endocrinol (Oxf) 1994;41:831-8. PubMed
- Perry W, Erooga MA, Brown J, Stamp TC. Calcium metabolism during rifampicin and isoniazid therapy for tuberculosis. J R Soc Med 1982;75:533-6. PubMed
- Shah SC, Sharma RK, Hemangini, Chitle AR. Rifampicin induced osteomalacia. Tubercle 1981;62:207-9. PubMed
- Brodie MJ, Boobis AR, Hillyard CJ, et al. Effect of rifampicin and isoniazid on vitamin D metabolism. Clin Pharmacol Ther 1982;32:525-30. PubMed
VITAMIN K
Moderate DepletionRIFAMPIN (Rifadin)
There are occasional reports of vitamin K deficiency associated with rifampin therapy, leading to prolonged clotting times and, in one case, a cerebral bleed. Suggested mechanisms include reduced intestinal absorption of vitamin K, destruction of vitamin K-producing intestinal bacteria, and interference with enzymes that regenerate vitamin K from its inactive metabolite. Symptomatic vitamin K deficiency is most likely to occur in people with poor dietary intake or other contributory factors. For information on foods that are rich in vitamin K, see our chart.
What Vitamin K does & food sources
Vitamin K is required for normal blood clotting and contributes to bone health.
Common food sources:
- Leafy green vegetables (spinach, kale, broccoli)
- Vegetable oils
- Fermented foods like natto
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
If you take warfarin, vitamin K intake is a central part of your therapy — consistency matters more than avoidance. Discuss any planned change in vitamin K intake (diet or supplements) with the clinic that manages your INR.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Never start or stop a vitamin K supplement on your own if you take warfarin — it directly changes how the medication works.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin K interacts with warfarin: keep intake consistent and involve your anticoagulation clinic in any change.
References (2)
- Kobayashi K, Haruta T, Maeda H, et al. Cerebral hemorrhage associated with vitamin K deficiency in congenital tuberculosis treated with isoniazid and rifampin. Pediatr Infect Dis J 2002;21:1088-90. PubMed
- Van Steenbergen W, Vermylen J. Reversible hypoprothrombinemia in a patient with primary biliary cirrhosis treated with rifampicin. Am J Gastroenterol 1995;90:1526-8.
This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
What drug-induced nutrient depletion means
Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.
Association is not deficiency
An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.
Evidence varies by pair
Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.
When to ask about labs
If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.
Don't self-supplement blindly
Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.
Never stop a medication over this
These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.
Food first, usually
For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.
Nutrient depletion FAQs
Can medications really deplete nutrients?
Does an entry in this checker mean I am deficient?
Should I take a supplement if my medication appears here?
What labs should I ask about?
Can supplements interact with my medications?
Where does this information come from, and how is it reviewed?
Not sure what your results mean?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations. The plain-English education is written and reviewed by licensed HelloPharmacist pharmacists.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this checker.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for medication overviews across the site.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.