Contraindicated in:

• Hypersensitivity to sulfonamides or trimethoprim;

• Megaloblastic anemia secondary to folate deficiency;

• Severe renal impairment;

• OB: Lactation: Pedi: Pregnancy, lactation, or children <2 mo (can cause kernicterus in neonates). Exception: neonates born to HIV-infected mothers (prophylaxis should be initiated at 4–6 weeks of age).

• Impaired hepatic or renal function (dose ↓ required if CCr <30 mL/min);

• HIV-positive patients (↑ incidence of adverse reactions).