Anti-TB — Individual Drug Adverse Effects
Four drugs, four organ targets. Confusing which TB drug damages which organ is one of the most common NCLEX pharmacology errors — and the stakes are liver failure, blindness, or permanent nerve damage.
Core Concept
Each RIPE drug carries a signature adverse effect tied to a specific organ. Rifampin is a potent CYP450 inducer that turns all body fluids orange-red (urine, tears, sweat) and reduces the effectiveness of oral contraceptives, warfarin, and HIV medications; it is also hepatotoxic. Isoniazid (INH) causes peripheral neuropathy by depleting pyridoxine (vitamin B6); supplementation with B6 25–50 mg daily is standard co-prescription. INH is also hepatotoxic, so baseline and periodic liver function tests (AST, ALT) are required for both INH and rifampin. Pyrazinamide elevates uric acid levels, causing hyperuricemia and potential gout flares; monitor uric acid and joint pain. Ethambutol targets the optic nerve — optic neuritis presents as decreased visual acuity and red-green color blindness; it is generally reversible if caught early and the drug is discontinued. A baseline eye exam is required before starting therapy, with monthly visual acuity and color discrimination testing throughout treatment. All four drugs can be hepatotoxic to varying degrees, but INH carries the highest hepatotoxicity risk. Teach the client to report dark urine, jaundice, persistent nausea, or unexplained fatigue immediately.
Watch Out For
Don't confuse rifampin's orange-red body fluids (harmless, expected) with dark amber urine (possible hepatotoxicity — requires evaluation). Students mix up ethambutol (eyes) and INH (nerves); remember Ethambutol = Eyes, INH = neuropathy needing B6. Pyrazinamide's hyperuricemia is distinct from renal toxicity — it mimics gout, not kidney failure.
Clinical Pearl
Think 'RIPE organ map': Rifampin → liver and fluids orange, Isoniazid → nerves (give B6), Pyrazinamide → joints (uric acid), Ethambutol → Eyes. Each letter points to its danger zone.
Test Your Knowledge
3 quick questions — see how well you understood Anti-TB — Individual Drug Adverse Effects