• Isoniazid

    Alternate Names :

    • INH

    Trade Names :

    • Laniazid
    • Nydrazid
    Vitamin B6 - Supplementation Likely Helpful Vitamin B3 - Supplementation Possibly Helpful Vitamin D - Supplementation Possibly Helpful
    Used for the treatment of tuberculosis, isoniazid can interfere with the absorption or metabolism of numerous nutrients. Since this antibiotic is commonly taken for a very long period of time, deficiencies can mount up over the course of treatment, impairing overall health.
    Vitamin B6
    Individuals who take isoniazid may develop nerve problems such as tingling or numbness in the arms, hands, legs, and feet. The cause is believed to be the drug's interference with the action of vitamin B 6 . 1,2 In fact, use of isoniazid is one cause of the few occasions in which vitamin B 6 deficiency is seen in the developed world. 3
    To prevent these complications, it may make sense to take vitamin B 6 supplements at a dose of 15 to 30 mg per day when using isoniazid.
    Vitamin B3
    According to animal studies, isoniazid can interfere with the body's ability to produce vitamin B 3 (niacin) by blocking a key enzyme. This can produce either a subtle or an all-out niacin deficiency (known as pellagra). 4,5,6 Taking niacin supplements at standard U.S. Dietary Reference Intake (formerly known as the Recommended Dietary Allowance) doses should help you get the niacin you need.
    Vitamin D
    Isoniazid may interfere with the body's ability to use vitamin D. 7,8,9
    Although it is not clear whether this actually causes symptoms of vitamin D deficiency, 10 it still might be a good idea to take vitamin D supplements at standard U.S. Adequate Intake (AI) dosages.


    1 Mandell GL and Petri WA Jr. Antimicrobial Agents: Drugs used in the chemotherapy of tuberculosis, Mycobacterium avium complex disease and leprosy. As cited in Goodman L and Gilman A. The pharmacological basis of therapeutics, 9th ed. Hardman J, et al (eds.). New York: McGraw-Hill, 1996: 1158.

    2Combs, G. The vitamins, 2nd ed. New York: Academic Press, 1992: 337, 344.

    3Shils M, et al. (eds.). Modern nutrition in health and disease, 9th ed. Baltimore: Williams and Wilkins, 1999: 1548.

    4 Ishii N and Nishihara Y. Pellagra encephalopathy among tuberculous patients: its relation to isoniazid therapy. J Neurol Neurosurg Psychiatry 48: 628–634, 1985.

    5 Shibata K, Marugami M, and Kondo T. In vivo inhibition of kynurenine aminotransferase activity by isonicotinic acid hydrazide in rats. Biosci Biotechnol Biochem 60: 874–876, 1996.

    6 DiLorenzo PA. Pellagra-like syndrome associated with isoniazid therapy. ActDermatol Venereol 47: 318–322, 1967.

    7 Brodie MJ, et al. Effect of isoniazid on vitamin D metabolism and hepatic monooxygenase activity. Clin Pharmacol Ther 30: 363–367, 1981.

    8 Bengoa JM, et al. Hepatic vitamin D 25-hydroxylase inhibition by cimetidine and isoniazid. J Lab Clin Med 104: 546–552, 1984.

    9Shils M, et al. (eds.). Modern nutrition in health and disease, 9th ed. Baltimore: Williams and Wilkins, 1999: 1634.

    10Shils M, et al. (eds.). Modern nutrition in health and disease, 9th ed. Baltimore: Williams and Wilkins, 1999: 1634.

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