SULSOXIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SULSOXIN (SULSOXIN).
Bactericidal; inhibits cell wall synthesis by binding to penicillin-binding proteins (PBPs) and disrupting peptidoglycan cross-linking.
| Metabolism | Primarily renally excreted unchanged; no significant hepatic metabolism. |
| Excretion | Renal: 70% (unchanged); biliary/fecal: 20%; minor hepatic metabolism (<10%) |
| Half-life | 8 hours (terminal) — extends in renal impairment (up to 24 hours in CrCl <30 mL/min); requires dose adjustment |
| Protein binding | 85–90% bound to albumin |
| Volume of Distribution | 1.2 L/kg — indicates extensive tissue distribution |
| Bioavailability | Oral: 75–90%; IM: 100% |
| Onset of Action | IV: 15 minutes; Oral: 1–2 hours; IM: 30–45 minutes |
| Duration of Action | IV: 6–8 hours; Oral: 8–12 hours; IM: 6–8 hours — prolonged in renal impairment |
500 mg orally 4 times daily for 10-14 days (or 1 g orally 4 times daily for severe infections).
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: 500 mg every 8 hours; CrCl 15-29 mL/min: 500 mg every 12 hours; CrCl <15 mL/min: 500 mg every 24 hours. |
| Liver impairment | No adjustment required for mild to moderate hepatic impairment; contraindicated in severe hepatic impairment (Child-Pugh class C). |
| Pediatric use | 8-12 mg/kg orally 4 times daily for 10 days; maximum 500 mg per dose. |
| Geriatric use | No specific dose adjustment; monitor renal function and adjust based on CrCl. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SULSOXIN (SULSOXIN).
| Breastfeeding | SULSOXIN is excreted into breast milk in small amounts. The M/P ratio for sulfadiazine is approximately 0.5–0.8; trimethoprim M/P ratio is about 1.0–1.5. Potential for kernicterus in nursing infants with G6PD deficiency or jaundice. Caution; monitor infant for rash, diarrhea, or changes in behavior. Use only if benefits outweigh risks. |
| Teratogenic Risk | SULSOXIN (sulfadiazine/trimethoprim) is contraindicated in pregnancy. First trimester: Associated with neural tube defects and cardiovascular anomalies due to folate antagonism from trimethoprim. Second and third trimesters: Risk of kernicterus in the neonate due to sulfadiazine displacing bilirubin from albumin, especially near term. Avoid if possible. |
■ FDA Black Box Warning
Not indicated for the treatment of syphilis; may mask or delay symptoms of incubating syphilis, requiring serologic follow-up.
| Serious Effects |
Hypersensitivity to sulfonamides (if sulfonamide component present) or any component of the formulation.
| Precautions | Hypersensitivity reactions including anaphylaxis; caution in renal impairment; may cause superinfection with prolonged use. |
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| Fetal Monitoring | Monitor complete blood count (CBC) with differential, renal function, and liver function tests at baseline and periodically. Assess for signs of hypersensitivity (Stevens-Johnson syndrome) or hemolytic anemia in G6PD-deficient patients. Fetal ultrasound to evaluate for congenital anomalies if exposed during first trimester. |
| Fertility Effects | Trimethoprim may impair folate metabolism, potentially reducing male fertility. No documented effect on female fertility. Reversible upon discontinuation. |