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 |
| Molecular Weight | 278.33 |
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 | Limited data; animal studies show no fetal risk, but human studies are insufficient. Use only if clearly needed. |
| 2nd trimester | No evidence of harm in second trimester; monitor fetal growth if prolonged use. |
| 3rd trimester | Possible risk of neonatal toxicity or withdrawal; avoid near term unless benefit outweighs risk. |
Clinical note
Comprehensive clinical and safety monograph for SULSOXIN (SULSOXIN).
| Placental transfer | Crosses placenta; achieves fetal serum concentrations 50-80% of maternal levels. |
| Breastfeeding | Excreted into breast milk in low concentrations; unlikely to cause adverse effects in infant. Monitor for diarrhea or rash. |
| Lactation Rating |
■ 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 sulfonamidesPorphyriaSevere hepatic impairmentInfants less than 2 months of age (except for treatment of congenital toxoplasmosis)
| Precautions | Hypersensitivity reactions including anaphylaxis; caution in renal impairment; may cause superinfection with prolonged use. |
| Food/Dietary | Avoid acidic foods and beverages (e.g., citrus fruits, tomatoes) as they may increase risk of crystalluria. Maintain adequate hydration; no specific food restrictions otherwise. |
Loading safety data…
| L2 (Probably Compatible) |
| 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. |
| 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. |
| Clinical Pearls |
| SULSOXIN is a sulfonamide antibiotic; ensure adequate fluid intake to prevent crystalluria. Monitor for hypersensitivity reactions, especially in patients with sulfa allergies. Avoid use in infants <2 months of age due to risk of kernicterus. |
| Patient Advice | Take exactly as prescribed; complete the full course even if you feel better. · Drink plenty of water to prevent kidney stones. · Avoid prolonged sun exposure; use sunscreen as this drug may cause photosensitivity. · Report any skin rash, fever, or sore throat immediately. · Do not take if you have a known allergy to sulfa drugs. |