Susceptible infections including UTIs (not for initial uncomplicated episodes), shigellosis, prophylaxis and treatment of Pneumocystis carinii pneumonia (PCP), travelers' diarrhea or acute exacerbations of chronic bronchitis in adults, acute otitis media in children.
1 DS tab, 2 regular tabs, or 20mL of susp every 12 hours for 5 days (shigellosis, travelers' diarrhea), or 10–14 days (UTIs), or 14 days (bronchitis). PCP treatment: 15–20mg/kg per day of trimethoprim (75–100mg/kg per day of sulfamethoxazole) in 4 divided doses at 6 hour intervals for 14–21 days; PCP prophylaxis: one DS tab daily.
<2months: not recommended. ≥2 months: 8mg/kg per day trimethoprim (40mg/kg per day of sulfamethoxazole) in 2 divided doses at 12 hour intervals for 5 days (shigellosis) or 10 days (otitis media, UTIs). PCP treatment: as adult; PCP prophylaxis or renal impairment: see literature.
Sulfonamide + folic acid inhibitor.
Megaloblastic anemia due to folate deficiency. 3rd trimester pregnancy (Cat.C). Infants. Nursing mothers of ill, stressed, G6PD-deficient, premature, or hyperbilirubinemic infants.
Not for group A β-hemolytic strep. Avoid prolonged administration. Monitor blood, urine, and renal function. Hepatic or renal dysfunction. AIDS (increased risk of toxicity). Folate or G6PD deficiency. Allergy. Asthma (inj). Maintain adequate hydration. Discontinue if rash occurs. Elderly. CrCl 15–30mL/min: reduce dose by ½; CrCl <15mL/min: not recommended.
May potentiate oral anticoagulants, hypoglycemics, phenytoin, methotrexate. May increase risk of thrombocytopenic purpura with diuretics (esp. thiazides). May form insoluble precipitate with methenamine metabolites.
GI upset, allergic skin reactions, blood dyscrasias, hemolysis, hepatic or renal toxicity, crystalluria, pancreatitis, photosensitivity, drug fever, rash (may be serious, eg, Stevens-Johnson syndrome, toxic epidermal necrolysis), lupus-like syndrome, peripheral neuritis, depression, convulsions, ataxia.
Tabs—100; DS tabs—20, 100, 500; Susp, Inj—contact supplier