Indications for Sulfamethoxazole/Trimethoprim:
Susceptible infections including UTIs (not for initial uncomplicated episodes), shigellosis, prophylaxis and treatment of Pneumocystis jiroveci pneumonia (PJP), 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 12hrs for 5 days (shigellosis, travelers' diarrhea), or 10–14 days (UTIs), or 14 days (bronchitis). PJP 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; PJP prophylaxis: one DS tab daily. Renal impairment (CrCl 15–30mL/min): reduce dose by ½; (CrCl <15mL/min): not recommended.
<2 months: see Contraindications. ≥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). PJP treatment: as adult; PJP prophylaxis or renal impairment: see full labeling.
History of drug-induced immune thrombocytopenia with use of trimethoprim and/or sulfonamides. Megaloblastic anemia due to folate deficiency. Children <2 months. Marked hepatic damage. Severe renal insufficiency when renal status cannot be monitored.
Not for group A β-hemolytic strep. Avoid prolonged administration. Monitor CBCs, urine, and renal function. Hepatic or renal dysfunction. AIDS (increased risk of toxicity). Folate or G6PD deficiency. Severe allergy. Bronchial asthma. Circulatory shock. Malnutrition. Porphyria. Thyroid dysfunction. Disorders of potassium metabolism. Monitor for electrolyte abnormalities. Maintain adequate hydration. Discontinue at the 1st sign of skin rash. Elderly. Pregnancy. Nursing mothers.
Sulfonamide + folic acid inhibitor.
Caution with concomitant CYP2C8, 2C9, or OCT2 substrates. May potentiate oral anticoagulants (eg, warfarin), hypoglycemics, phenytoin, methotrexate, digoxin. May be potentiated by indomethacin. May increase risk of thrombocytopenia with diuretics (esp. thiazides). Nephrotoxicity with cyclosporine in renal transplant. Megaloblastic anemia with >25mg/week doses of pyrimethamine. May antagonize tricyclic antidepressants. May interfere with assays for serum methotrexate, creatinine. PJP treatment: avoid leucovorin.
Nausea, vomiting, anorexia, allergic skin reactions, blood dyscrasias (eg, thrombocytopenia, aplastic anemia, agranulocytosis), hemolysis, hepatic or renal toxicity, crystalluria, pancreatitis, photosensitivity, drug fever, rash (may be serious, eg, Stevens-Johnson syndrome, toxic epidermal necrolysis, others), lung injury, lupus-like syndrome, peripheral neuritis, depression, convulsions, ataxia, hypoglycemia, hyperkalemia, hyponatremia; C. difficile-associated diarrhea.
Formerly known under the brand name Septra.