How should rifampin be discussed with patients regarding drug interactions?

• A. It induces hepatic enzymes, lowering levels of many drugs; plan accordingly and monitor for interactions
• B. It has no interactions
• C. It increases levels of all drugs
• D. It only interacts with antidepressants

Answer: (A)

Rifampin is a potent inducer of hepatic enzymes, especially CYP450 enzymes like CYP3A4, and drug transporters. This speeds up the metabolism and clearance of many other medicines, so their levels can fall and their effectiveness can be reduced. When discussing this with patients, emphasize that starting rifampin can alter how other drugs work, often requiring dose adjustments, alternative therapies, or closer monitoring of effects and, where available, drug levels. Because enzyme induction develops over days to weeks and rifampin can auto-induce its own metabolism, plans may need to be revisited after initiation. Encourage patients to tell every clinician about rifampin, review all medications (including hormonal contraceptives, anticoagulants, antiretrovirals, statins, and more), and report any signs that a drug is not working or is causing interactions. The other statements are not correct because rifampin does interact with many drugs, typically lowering their levels rather than increasing them, and its interactions are not limited to antidepressants.