Isoniazid (drug interactions)
Isoniazid is an antibiotic commonly prescribed for the treatment of tuberculosis. However, it is important for patients and healthcare providers to be aware of its potential drug interactions. Notably, isoniazid can interfere with the metabolism of several vitamins, including vitamin B6, B3 (niacin), and vitamin D. Supplementation with vitamin B6 is generally recommended to prevent nerve-related side effects associated with isoniazid use. Additionally, there is a possibility of niacin deficiency, so niacin supplementation may also be beneficial.
Isoniazid users should avoid St. John’s wort, as it may reduce the drug’s effectiveness, and foods high in tyramine, which can lead to dangerous spikes in blood pressure. Alcohol consumption should be limited as it can worsen liver toxicity, a known side effect of isoniazid. Moreover, aluminum-based antacids can hinder the absorption of the drug, and patients taking various antidepressants, anticonvulsants, or heart medications should consult their healthcare provider to discuss potential interactions. Understanding these interactions can help ensure safe and effective treatment with isoniazid.
Subject Terms
Isoniazid (drug interactions)
DEFINITION: An antibiotic drug used for the treatment of tuberculosis.
INTERACTIONS: Vitamin B3, vitamin B6, vitamin D, St. John's wort, tyramine, alcohol, antacids, various prescription medications
TRADE NAMES: Laniazid, Nydrazid
Vitamin B6
Effect: Supplementation Likely Helpful
Persons 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 vitamin B6's action. The use of isoniazid is one of the few occasions in which vitamin B6 deficiency is seen in the developed world.
To prevent these complications, people who use isoniazid should take vitamin B6 supplements at a dose of 15 to 30 milligrams per day.
Vitamin B3
Effect: Supplementation Possibly Helpful
According to animal studies, isoniazid can block a key enzyme in the body’s ability to produce vitamin B3 (niacin), producing either a subtle or an all-out niacin deficiency (known as pellagra). Taking niacin supplements at standard US Dietary Reference Intake (formerly known as the Recommended Dietary Allowance) doses should help a person get the needed niacin.
Vitamin D
Effect: Supplementation Possibly Helpful
Isoniazid may interfere with the body’s ability to use vitamin D. Although it is not clear whether this actually causes symptoms of vitamin D deficiency, it might still be a good idea to take vitamin D supplements at standard US Adequate Intake (AI) dosages.
Other Interactions
Several other interactions exist between isoniazid and various herbs, supplements, and prescription medications. Patients taking isoniazid should not take St. John's wort, as it may induce liver enzymes and decrease the effectiveness of isoniazid. Foods containing high levels of tyramine should also be avoided, as when combined with isoniazid, they may cause high blood pressure and headaches. Alcohol can also increase the toxic effects on the liver, which is already a side effect of isoniazid. Patients should also avoid taking aluminum-based antacids, as they can interfere with the absorption of isoniazid. Finally, because various antidepressants, anticonvulsants, and heart medications can interfere with isoniazid, patients should discuss all substances they are taking with their healthcare provider.
Bibliography
Ishii, N., and Y. Nishihara. "Pellagra Encephalopathy Among Tuberculous Patients: Its Relation to Isoniazid Therapy." Journal of Neurology, Neurosurgery, and Psychiatry, vol. 48, 1985, pp. 628-634.
"Isoniazid – Health Information Library." PeaceHealth, www.peacehealth.org/medical-topics/id/hn-1404000. Accessed 11 Sept. 2024.
"Isoniazid (Oral Route, Intramuscular Route)." Mayo Clinic, 1 Sept. 2024, www.mayoclinic.org/drugs-supplements/isoniazid-oral-route-intramuscular-route/precautions/drg-20064419?p=1. Accessed 11 Sept. 2024.
"Isoniazid/Rifampin and Alcohol/Food Interactions." Drugs.com, www.drugs.com/food-interactions/isoniazid-rifampin.html. Accessed 11 Sept. 2024.
Mandell, G. L., and W. A. Petri. "Antimicrobial Agents: Drugs Used in the Chemotherapy of Tuberculosis, Mycobacterium avium Complex Disease, and Leprosy." In Goodman and Gilman’s The Pharmacological Basis of Therapeutics, edited by Laurence L. Brunton et al. 11th ed., New York: McGraw-Hill Medical, 2011.