Chloramphenicol & Nutrient Depletion
Also searched as Chloromycetin, Chloromycetin Ophthalmic, Chloromycetin Injection. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Chloramphenicol has been associated with depletion of BIOTIN, FOLIC ACID, RIBOFLAVIN and THIAMINE and 4 more. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Chloramphenicol long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Chloramphenicol pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Chloramphenicol
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.
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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.
Biotin is a B vitamin your body uses to turn food into energy and keep your skin, hair, and nerves healthy. The concern with chloramphenicol, like other antibiotics, is that it can disrupt the friendly bacteria living in your gut, and those bacteria do make a small amount of biotin that your body can absorb. That said, gut bacteria only cover a modest slice of your daily biotin needs, and clinical research has not actually shown that antibiotics cause a meaningful drop in biotin levels. For most people taking chloramphenicol, this is not something that requires action, though you are always welcome to ask your pharmacist if you have questions.
Learn more about this nutrient: Biotin — uses, safety & interactions
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.
Folic acid is a B vitamin your body needs to build healthy cells and keep your DNA in good shape. Chloramphenicol, like other antibiotics, can temporarily disrupt the natural bacteria living in your gut, and those bacteria normally help with folate absorption and even produce small amounts of it themselves. That said, the evidence rates this as an insignificant concern, meaning most people taking chloramphenicol do not need to add a folate supplement. If you have questions about your own situation, a quick conversation with your pharmacist or doctor can put your mind at ease.
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)
- 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.
Riboflavin, which your body relies on for turning food into energy and keeping skin and nerves healthy, can theoretically dip a little when you take chloramphenicol. The antibiotic alters the normal bacteria living in your gut, and those bacteria do produce small amounts of riboflavin. That said, your diet supplies the vast majority of what your body needs, so this is considered an insignificant concern for most people. No riboflavin supplement is typically needed during a course of chloramphenicol, but feel free to mention it to your pharmacist if you have questions.
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)
- 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.
Thiamine is a B vitamin your body counts on for turning food into energy and keeping your nerves working properly. Chloramphenicol is an antibiotic, and like other antibiotics it can disrupt the helpful bacteria living in your gut, which normally produce small amounts of thiamine. That sounds concerning, but here is the reassuring part: you get the vast majority of your thiamine from the food you eat, not from gut bacteria, so this interaction is considered insignificant for most people. No supplement is typically needed, but if you have questions about your diet or how you are feeling while on this medication, your pharmacist or doctor is a good person to ask.
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)
- 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.
Vitamin B12 is something your nerves and red blood cells genuinely depend on, so it is worth knowing where it fits here. Chloramphenicol is an antibiotic, and antibiotics in general can shift the balance of bacteria living in your gut, which plays a small role in how B12 is recycled through your digestive system. That said, the effect on your actual B12 levels is considered insignificant, meaning most people taking this medication do not need to worry about a deficiency or take a supplement because of it. If you have any concerns, a quick conversation with your pharmacist or doctor can put your mind at ease.
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)
- 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.
Vitamin B6 helps your body make energy from food and keeps your nervous system running properly. There is an old idea that antibiotics like chloramphenicol might reduce B6 by wiping out the friendly bacteria in your gut, since those bacteria can produce small amounts of B6. In practice, though, your gut bacteria are not a meaningful source of this vitamin for humans, so this concern is considered insignificant. Most people taking chloramphenicol do not need to do anything extra about B6, but feel free to mention it to your pharmacist if you have questions.
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)
- 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 DepletionCHLORAMPHENICOL
Chloramphenicol may interfere with the activity of NAD and has been reported to cause pellagra. Details of cases are lacking, but pellagra is probably unlikely to occur unless therapy with chloramphenicol is prolonged.
Niacin is a B vitamin your body uses to produce energy from food and keep your skin, nerves, and digestion working properly. Chloramphenicol appears to interfere with how your body activates and uses niacin at the cellular level, which in rare cases has been linked to pellagra, a condition caused by severe niacin deficiency. That said, this seems most relevant for people on prolonged courses of the antibiotic, not short-term use. If you are taking chloramphenicol for an extended period, it is worth bringing up with your pharmacist or doctor to see whether any monitoring or support 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 (5)
- Stratigos JD, Katsambas A. Pellagra: a still existing disease. Br J Dermatol 1977;96:99-106. PubMed
- Nahata MC. Chloramphenicol. In: Evans WE, Schentag JJ, Jusko WJ (eds). Applied Pharmacokinetics: Principles of Therapeutic Drug Monitoring. 3rd ed., Vancouver, WA: Applied Therapeutics, Inc., 1992.
- Bingham LG, Verma SB. A photodistributed rash. (Self-Assessment examination of the American Academy of Dermatology). J Am Acad Dermatol 2005;52:929-32. DOI
- Hendricks WM. Pellagra and pellagralike dermatoses: etiology, differential diagnosis, dermatopathology, and treatment. Semin Dermatol 1991;10:282-92.
- Karthikeyan K, Thappa DM. Pellagra and skin. Int J Dermatol 2002;41:476-81.
VITAMIN K
Moderate DepletionANTIBIOTIC DRUGS
Vitamin K produced by intestinal bacteria is absorbed from the ileum. This contribution to overall vitamin K status is unclear, and likely varies. Destruction of vitamin K-producing bacteria by antibiotics can sometimes lead to vitamin K deficiency, prolonging clotting times and increasing bleeding risk. It's suggested that antibiotics such as cefamandole that are secreted into the bile in large amounts have a greater effect on vitamin K-producing bacteria. Also, some cephalosporins have a methylthiotetrazole side chain that may interfere with vitamin K activity, directly inhibiting clotting factor production in the liver. These cephalosporins include cefamandole, cefoperazone, cefmetazole, and cefotetan. This interaction is most likely to occur with prolonged antibiotic therapy (10 days or more) in people with poor dietary vitamin K intake. Vitamin K supplements aren't necessary for otherwise healthy people taking short courses of antibiotics. For information on foods that are rich in vitamin K, see our chart.
Vitamin K is something your body needs to form blood clots and stop bleeding properly. Chloramphenicol is an antibiotic, and like other antibiotics used for longer courses, it can wipe out some of the helpful bacteria living in your gut that normally produce a portion of your vitamin K. This is more of a concern if you have been on the antibiotic for 10 days or more and are not getting much vitamin K through food. If your treatment is extended, it is worth checking in with your pharmacist or doctor about whether any monitoring or extra vitamin K makes sense for you.
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 (8)
- Hill MJ. Intestinal flora and endogenous vitamin synthesis. Eur J Cancer Prev 1997;6:S43-5. PubMed
- Conly JM, Stein K, Worobetz L, Rutledge-Harding S. The contribution of vitamin K2 (menaquinones) produced by the intestinal microflora to human nutritional requirements for vitamin K. Am J Gastroenterol 1994;89:915-23.
- 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.
- Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2002.
- Haubenstock A, Schmidt P, Zazgornik J, Balcke P, Kopsa H. Hypoprothrombobinaemic bleeding associated with ceftriaxone. Lancet 1983;1:1215-6.
- Hooper CA, Haney BB, Stone HH. Gastrointestinal bleeding due to vitamin K deficiency in patients on parenteral cefamandole. Lancet 1980;1:39-40. PubMed
- Bhat RV, Deshmukh CT. A study of Vitamin K status in children on prolonged antibiotic therapy. Indian Pediatr 2003;40:36-40.
- Sattler FR, Weitekamp MR, Ballard JO. Potential for bleeding with the new beta-lactam antibiotics. Ann Intern Med 1986;105:924-31. PubMed
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.
More about Chloramphenicol
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.
Chloramphenicol & nutrients: FAQs
Does Chloramphenicol deplete BIOTIN?
Should I take a supplement because I take Chloramphenicol?
Should I stop taking Chloramphenicol?
Where does this information come from?
Questions about Chloramphenicol and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Chloramphenicol are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- 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.