Topic overview

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For tuberculosis, the first-line RIPE combination comprises rifampin, isoniazid, pyrazinamide, and ethambutol. Each acts through a different mechanism: rifampin inhibits RNA polymerase, isoniazid blocks mycolic acid synthesis, pyrazinamide disrupts membrane potential, and ethambutol inhibits cell wall synthesis. Combining drugs helps address resistance, which can arise through target-enzyme mutations. Important adverse effects include hepatotoxicity with rifampin, isoniazid, and pyrazinamide; optic neuritis with ethambutol; and peripheral neuropathy with isoniazid. For leprosy, dapsone, rifampin, and clofazimine are used together. The broader lesson also covers drug-resistant TB, treatment regimens, interactions, and contraindications.