Sulfamethoxazole/trimethoprim Injection

  • Bacterial infections

Sulfamethoxazole/trimethoprim Injection Generic Name & Formulations

General Description

Sulfamethoxazole 80mg, trimethoprim 16mg; per mL; contains sulfites, benzyl alcohol.

Pharmacological Class

Sulfonamide + folic acid inhibitor.

How Supplied

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Sulfamethoxazole/trimethoprim Injection Indications


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

Sulfamethoxazole/trimethoprim Injection Dosage and Administration

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.

Sulfamethoxazole/trimethoprim Injection Contraindications


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. Concomitant dofetilide.

Sulfamethoxazole/trimethoprim Injection Boxed Warnings

Not Applicable

Sulfamethoxazole/trimethoprim Injection Warnings/Precautions


Not for group A β-hemolytic strep. Avoid prolonged administration. Monitor CBCs, urine, and renal function. Hepatic or renal impairment: avoid. 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 or any other serious reaction. Elderly. Embryo-fetal toxicity. Pregnancy. Nursing mothers (IV: not recommended).

Sulfamethoxazole/trimethoprim Injection Pharmacokinetics

See Literature

Sulfamethoxazole/trimethoprim Injection Interactions


See Contraindication. 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.

Sulfamethoxazole/trimethoprim Injection Adverse Reactions

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, drug reaction with eosinophilia and systemic symptoms, others), fulminant hepatic necrosis, lung injury, lupus-like syndrome, peripheral neuritis, depression, convulsions, ataxia, hypoglycemia, hyperkalemia, hyponatremia; C. difficile-associated diarrhea, thrombocytopenia.

Sulfamethoxazole/trimethoprim Injection Clinical Trials

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Sulfamethoxazole/trimethoprim Injection Note


Formerly known under the brand name Septra.

Sulfamethoxazole/trimethoprim Injection Patient Counseling

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