Pyrazinamide

PZA

What it isA first-line TB prodrug activated by mycobacterial pyrazinamidase to pyrazinoic acid, active on dormant organisms in acidic foci.

Why this oneIts sterilizing effect on semi-dormant bacilli is what shortened TB therapy from nine months to six.

What limits itHepatotoxicity is the most frequent of the first-line drugs, and it reliably raises uric acid — gout flares are expected.

FDA label

FDA dosing	Population	Start	Target	Max
Tuberculosis, drug-susceptible — initial 2 months of >=6-month regimen (always with other antituberculous drugs)	Adults & children	15-30 mg/kg QD	15-30 mg/kg QD	2 g/day (CDC daily regimen); never exceed 3 g/day
Tuberculosis — intermittent (compliance) regimen	Adults & children	50-70 mg/kg twice weekly (lean body weight)	50-70 mg/kg twice weekly	—

Renal Undefined

Hepatic Contraindicated with severe hepatic damage

Always administer with other effective antituberculous drugs
Drug-resistant disease: individualized regimen; HIV coinfection may require longer courses

Hepatotoxicity is the principal adverse effect — dose related, may appear at any time during therapy
Gout (hyperuricemia)

Hepatic reaction / hepatotoxicity (principal adverse effect)
Nausea, vomiting, anorexia
Arthralgia and myalgia (frequent, mild); gout
Rash, urticaria, pruritus; photosensitivity
Rare: thrombocytopenia, sideroblastic anemia, clotting abnormalities, fever, porphyria, dysuria, interstitial nephritis, acne

Pregnancy Category C — no animal reproduction studies; unknown fetal risk; give only if clearly needed

Lactation Undefined

NO BOXED WARNINGS