Pyrazinamide Data - Uses, Dosage, Drug class, Brand name, Warnings, etc

Pharmacology	Pyrazinamide is a synthetic analogue of niacinamide, active only against mycobacteria. Mode of action unknown; most effective at acidic pH, targeting intracellular organisms. Resistance develops rapidly when used alone; no cross-resistance with isoniazid.
Adult Dosage	PO for latent tuberculosis infection: - Daily: 15–20 mg/kg/day (max 2 g) with rifampin 10 mg/kg/day (max 600 mg) as a single dose for 2 months - Twice weekly (DOT): 50 mg/kg/dose (max 4 g) with rifampin 10 mg/kg/dose (max 600 mg) for 2–3 months PO for active tuberculosis: - See isoniazid dosage for combination regimens
Dosage Forms	- Tablet: 500 mg - Combination Tablet (Rifater): Pyrazinamide 300 mg + isoniazid 50 mg + rifampin 120 mg
Pharmacokinetics	Absorption: - Well absorbed from GI tract Peak Serum Concentration: - 40–50 mg/L (0.3–0.4 mmol/L) 2 hr post 1 g dose - 20–60 mg/L (163–488 µmol/L) 2 hr post 1–2 g dose (adequate absorption) Excretion: - Parent compound and metabolites primarily in urine
Adverse Reactions	Frequent: - Hyperuricemia (due to metabolite inhibition of uric acid excretion) Occasional: - Dose-dependent hepatotoxicity - 1–5% of patients on isoniazid-rifampin-pyrazinamide regimens show hepatic enzyme elevations