Drug General Information (ID: DDITQ15XN6)
Drug Name			Isoniazid		Drug Info		Rifampicin		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antitubercular Agents				Antituberculosis Agents
Structure

Mechanism of Isoniazid-Rifampicin Interaction (Severity Level: Minor)
Increased risk of hepatotoxicity Click to Show/Hide Mechanism Graph
Drug Name		Isoniazid				Rifampicin
Mechanism		Hepatotoxicity				Hepatotoxicity
Key Mechanism Factor 1
		Factor Name		Hepatotoxicity
		Factor Description		Combination of drugs that can induce hepatotoxicity may increase the risk of liver injury. Symptoms vary depending on the level of exposure and the total extent of liver damage, and may cause few symptoms if the damage is mild, and eventually lead to liver failure in patients with severe damage.
Mechanism Description		Increased risk of hepatotoxicity by the combination of Isoniazid and Rifampicin

Recommended Action
Management		Close monthly monitoring for clinical or laboratory evidence of altered hepatic function is recommended. Patients should be advised to promptly report early symptoms of hepatitis such as fatigue, weakness, malaise, anorexia, nausea, or vomiting. Discontinuation of either or both drugs may be necessary.

References
1	Askgaard DS, Wilcke T, Dossing M "Hepatotoxicity caused by the combined action of isoniazid and rifampicin." Thorax 50 (1995): 213-4. [PMID: 7701468]
2	Product Information. Mycobutin (rifabutin). Pharmacia and Upjohn, Kalamazoo, MI.
3	Yamamoto T, Suou T, Hirayama C "Elevated serum aminotransferase induced by isoniazid in relation to isoniazid acetylator phenotype." Hepatology 6 (1986): 295-8. [PMID: 3957235]