Bacterial infections:

Indications for Sulfamethoxazole/Trimethoprim Injection:

Susceptible Pneumocystis jiroveci pneumonia (PJP), shigellosis, severe or complicated UTIs.

Adults and Children:

Dilute (see full labeling); give IV over 60–90 minutes. <2months: not recommended. ≥2months: PJP: 15–20mg/kg per day (of trimethoprim) in 3–4 equal divided doses every 6–8 hours for up to 14 days. Shigellosis, UTIs: 8–10mg/kg per day (of trimethoprim) in 2–4 equal divided doses every 6, 8, or 12 hours for up to 5 days (for shigellosis) or up to 14 days (for UTIs). Max 60mL/day.


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. Malnutrition. Porphyria. Thyroid dysfunction. Disorders of potassium metabolism. Monitor for electrolyte abnormalities. Maintain adequate hydration. Discontinue if rash occurs. Elderly. Pregnancy (Cat.D). Nursing mothers.

Pharmacologic Class:

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.

Adverse Reactions:

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), lupus-like syndrome, peripheral neuritis, depression, convulsions, ataxia, hypoglycemia, hyperkalemia, hyponatremia; C. difficile-associated diarrhea.

How Supplied:

Tabs—100; DS tabs—20, 100, 250, 500; Susp, Inj—contact supplier