Drug-induced nutrient depletion

Isoniazid, Rifampin & Nutrient Depletion

Also searched as Rifamate. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.

9Nutrient associations
Insignificant DepletionHighest rating
The bottom line

Isoniazid, Rifampin has been associated with depletion of BIOTIN, FOLIC ACID, RIBOFLAVIN and THIAMINE and 5 more. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Isoniazid, Rifampin long-term, worth raising with your pharmacist or healthcare provider.

Ask a pharmacist about Isoniazid, Rifampin Free · usually answered within 24 hours

Take more than one medication? Open the checker with Isoniazid, Rifampin pre-loaded and add the rest to see overlapping nutrient signals.

The evidence

Reported nutrient depletions with Isoniazid, Rifampin

Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.

BIOTIN

Insignificant Depletion

ANTIBIOTIC DRUGS

There is some concern that antibiotic drugs might reduce biotin levels, but this has not been demonstrated in clinical research.
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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Biotin is a B vitamin your body uses to turn food into energy and keep your skin, hair, and nails healthy. The idea here is that antibiotics like isoniazid and rifampin might reduce the friendly gut bacteria that produce a small amount of biotin, but that bacterial source accounts for less than a fifth of what most people need each day. Research has not actually shown a real drop in biotin levels from these medications, so this is considered an insignificant concern for the vast majority of patients. No action is needed for most people, but if you have questions, your pharmacist or doctor is a good person to ask.

Learn more about this nutrient: Biotin — uses, safety & interactions

References (4)
  1. Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
  2. Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
  3. 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
  4. 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 Depletion

ANTIBIOTIC DRUGS

Theoretically, antibiotics might reduce folate absorption; however, this is not likely to be clinically significant.

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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Folic acid is a B vitamin your body uses to build new cells and keep your blood healthy. The thinking here is that antibiotics like isoniazid and rifampin can disrupt the natural bacteria living in your gut, and those bacteria normally help with folate recycling and even produce a small amount of it themselves. In practice, though, this effect appears to be minimal, and most people on these medications do not need a folic acid supplement because of it. If you have questions about your diet or whether a supplement makes sense for your situation, your pharmacist or doctor is a good person to ask.

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.

Learn more about this nutrient: Folic Acid — uses, safety & interactions

References (5)
  1. Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
  2. Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
  3. Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
  4. 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
  5. 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 Depletion

ANTIBIOTIC DRUGS

Antibiotic drugs might reduce riboflavin levels; however, this is not likely to be clinically significant.
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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Riboflavin, a B vitamin your body uses for energy production and keeping skin and nerves healthy, is mostly absorbed from the foods you eat rather than made by gut bacteria. When antibiotics like isoniazid and rifampin alter the normal bacteria living in your gut, that bacterial source of riboflavin can drop a little, but since diet is the real supplier, this rarely adds up to anything meaningful. The evidence rates this as insignificant for most people, so a riboflavin supplement is generally not needed during this therapy. That said, if you have questions about your nutrition while on these medications, your pharmacist or doctor is a good place to start.

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.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

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.

Learn more about this nutrient: Riboflavin — uses, safety & interactions

References (3)
  1. Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
  2. 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
  3. 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 Depletion

ANTIBIOTIC DRUGS

Theoretically, antibiotics might reduce thiamine absorption; however, this is not likely to be clinically significant.
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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Thiamine is a B vitamin your body needs for energy production and healthy nerve function. There is a theoretical idea that antibiotics like isoniazid and rifampin could slightly reduce the amount of thiamine bacteria in your gut normally produce, but here is the reassuring part: your diet, not your gut bacteria, supplies the vast majority of your daily thiamine anyway. The evidence rates this as insignificant, meaning most people on these medications do not need a thiamine supplement. No action is needed for most patients, but feel free to bring it up with your pharmacist or doctor if you have concerns.

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.

Learn more about this nutrient: Thiamine — uses, safety & interactions

References (1)
  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 Depletion

ANTIBIOTIC DRUGS

Antibiotics might reduce the absorption of vitamin B12, but this effect is unlikely to be clinically significant.

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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Vitamin B12 is something your nerves and red blood cells genuinely depend on, so it is worth understanding this one. When antibiotics like isoniazid and rifampin alter the normal bacteria living in your gut, there is a theoretical possibility that slightly less B12 gets recycled back into your system through a process involving the intestines and liver. In practice, though, this effect is considered insignificant, and a B12 supplement is not needed for most people taking these medications. If you have any concerns, your pharmacist or doctor is a good person to ask.

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.

Learn more about this nutrient: Vitamin B12 — uses, safety & interactions

References (3)
  1. Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
  2. Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
  3. 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 Depletion

ANTIBIOTIC DRUGS

Theoretically, antibiotics might reduce levels of vitamin B6 in the blood.

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.
Taking Isoniazid, Rifampin? A supplement is not needed for most patients.
Dr. Brian Staiger, Pharm.D explains

Isoniazid, one of the main tuberculosis drugs in this combination, has a well-known chemical quirk: it binds to vitamin B6 (which your nerves depend on to work properly) and locks it into an inactive form your body cannot use. Your kidneys then flush that inactive complex out, gradually drawing down your B6 stores. At standard doses this is not a problem for most people, but those on higher doses or with risk factors like diabetes, poor nutrition, or a history of seizures may need a supplement. It is worth bringing up with your doctor or pharmacist so they can decide whether monitoring or a B6 supplement makes sense for you.

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.

Learn more about this nutrient: Vitamin B6 — uses, safety & interactions

References (3)
  1. Gorbach SL. Bengt E. Gustafsson memorial lecture. Function of the normal human microflora. Scand J Infect Dis Suppl 1986;49:17-30.
  2. Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
  3. 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 Depletion

ISONIAZID

Isoniazid might indirectly reduce levels of niacin and precipitate niacin deficiency.

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.
Taking Isoniazid, Rifampin? Monitor for depletion; a supplement is needed for some patients.
Dr. Brian Staiger, Pharm.D explains

Niacin is a B vitamin your body uses for energy, healthy skin, and nerve function, and isoniazid can chip away at your levels in a couple of ways. It depletes vitamin B6 (pyridoxine), and your body actually needs B6 to convert the amino acid tryptophan into niacin, so losing B6 sets off a chain reaction. Isoniazid may also interfere with how niacin gets activated inside your cells. This is rated a moderate concern, meaning some long-term users, especially those with low dietary niacin, can develop real symptoms, so it is worth asking your doctor or pharmacist whether a B vitamin supplement makes sense for you.

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.

HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.

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.

Learn more about this nutrient: Niacin — uses, safety & interactions

References (6)
  1. Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease. 9th ed. Baltimore, MD: Williams & Wilkins, 1999.
  2. Ishii N, Nishihara Y. Pellagra encephalopathy among tuberculous patients: its relation to isoniazid therapy. J Neurol Neurosurg Psychiatry 1985;48:628-34. PubMed
  3. 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
  4. Darvay A, Basarab T, McGregor JM, Russell-Jones R. Isoniazid induced pellagra despite pyridoxine supplementation. Clin Exp Dermatol 1999;24:167-9. PubMed
  5. Stratigos JD, Katsambas A. Pellagra: a still existing disease. Br J Dermatol 1977;96:99-106. PubMed
  6. Bender DA, Russell-Jones R. Isoniazid-induced pellagra despite vitamin B6 supplementation (letter). Lancet 1979;2:1125-6. PubMed

VITAMIN D

Moderate Depletion

RIFAMPIN (Rifadin)

Rifampin might reduce blood levels of vitamin D.
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.
Taking Isoniazid, Rifampin? Monitor for depletion; a supplement is needed for some patients.
Dr. Brian Staiger, Pharm.D explains

Vitamin D is something your bones and immune system genuinely depend on, so this interaction is worth understanding. Rifampin is a strong enzyme inducer, meaning it revs up the liver's ability to break down vitamin D faster than normal, which can lower the usable form in your blood. The interesting twist here is that when isoniazid is taken alongside rifampin, as it usually is, isoniazid appears to blunt that effect, and studies suggest vitamin D levels may actually stay stable in people taking both together. That said, this is rated as moderate depletion, so if you have been on this combination for a long time or your diet is low in vitamin D, it is worth bringing up with your doctor or pharmacist.

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.

Learn more about this nutrient: Vitamin D — uses, safety & interactions

References (5)
  1. 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
  2. Kovacs CS, Jones G, Yendt ER. Primary hyperparathyroidism masked by antituberculous therapy-induced vitamin D deficiency. Clin Endocrinol (Oxf) 1994;41:831-8. PubMed
  3. 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
  4. Shah SC, Sharma RK, Hemangini, Chitle AR. Rifampicin induced osteomalacia. Tubercle 1981;62:207-9. PubMed
  5. 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 Depletion

RIFAMPIN (Rifadin)

Rifampin might decrease levels of vitamin K.

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.
Taking Isoniazid, Rifampin? Monitor for depletion; a supplement is needed for some patients.
Dr. Brian Staiger, Pharm.D explains

Vitamin K is something your body needs to form blood clots properly, and rifampin can work against it in a few ways: it may reduce how much vitamin K your gut absorbs, it can disrupt the intestinal bacteria that actually produce vitamin K, and it may interfere with the enzymes that recycle vitamin K back into its active form. Most healthy people eating a balanced diet handle this without trouble, but if your dietary intake is limited or you have other health factors in play, this becomes more worth watching. Because this is rated as moderate depletion, it is reasonable to bring it up with your pharmacist or doctor, especially if you are on rifampin long-term.

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.

Learn more about this nutrient: Vitamin K — uses, safety & interactions

References (2)
  1. 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
  2. Van Steenbergen W, Vermylen J. Reversible hypoprothrombinemia in a patient with primary biliary cirrhosis treated with rifampicin. Am J Gastroenterol 1995;90:1526-8.
Important

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.
Understand the basics

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.

Common questions

Isoniazid, Rifampin & nutrients: FAQs

Does Isoniazid, Rifampin deplete BIOTIN?
Isoniazid, Rifampin has been associated with lower BIOTIN levels in the clinical literature — see the evidence rating and details above. An association is not a guarantee: dose, duration, diet, and your own health all matter. If you take Isoniazid, Rifampin long-term, ask your healthcare provider whether checking your BIOTIN status is appropriate.
Should I take a supplement because I take Isoniazid, Rifampin?
Not automatically. The right first step is usually a conversation with your pharmacist or provider — they can weigh your dose and duration, decide whether testing makes sense, and recommend food-first strategies or a supplement if genuinely needed. Some supplements can interact with medications, so do not add one without checking.
Should I stop taking Isoniazid, Rifampin?
No — never stop a prescribed medication because of a nutrient association. Isoniazid, Rifampin is prescribed for good reasons, and nutrient considerations are usually manageable with monitoring or diet. Any change to your medication belongs in a conversation with your prescriber.
Where does this information come from?
The depletion records come from the Natural Medicines (Therapeutic Research Center) database — an evidence-graded clinical reference — and are displayed as published, with their citations. The plain-English context is written and reviewed by licensed HelloPharmacist pharmacists.

Questions about Isoniazid, Rifampin and your nutrition?

Ask a licensed pharmacist — free, no appointment needed.

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Sources

Sources & How We Checked

Nutrient depletion records for Isoniazid, Rifampin are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.