SULSTER
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SULSTER (SULSTER).
Sulster is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, blocking folate synthesis and thus bacterial DNA replication.
| Metabolism | Primarily hepatic metabolism via acetylation and glucuronidation; minor CYP450 involvement. |
| Excretion | Primarily renal (60-70% unchanged), with 20-30% as glucuronide conjugate; biliary/fecal <10%. |
| Half-life | Terminal half-life 3.5-4.5 hours in normal renal function; prolonged to 10-15 hours with creatinine clearance <30 mL/min. |
| Protein binding | 92-97% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.2-0.3 L/kg (10-15 L) indicating limited extravascular distribution, primarily confined to plasma and interstitial fluid. |
| Bioavailability | Oral: 75-85%; rectal: 50-60%; no significant first-pass metabolism. |
| Onset of Action | Oral: 1-2 hours; IV: within 15-30 minutes. |
| Duration of Action | Oral: 8-12 hours; IV: 4-6 hours, with dose-dependent prolongation at higher doses. |
2.5 mg orally twice daily.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | GFR ≥30 mL/min: no adjustment; GFR 15-29 mL/min: 2.5 mg once daily; GFR <15 mL/min not recommended. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: 2.5 mg once daily; Child-Pugh Class C: not recommended. |
| Pediatric use | Not established for patients <18 years. |
| Geriatric use | No specific dose adjustment; monitor renal function and electrolyte levels regularly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SULSTER (SULSTER).
| Breastfeeding | Contraindicated during breastfeeding. No human data on M/P ratio; drug is excreted in animal milk. Potential for serious adverse reactions in nursing infants. |
| Teratogenic Risk | Pregnancy Category X. First trimester: High risk of major congenital malformations including craniofacial defects, cardiovascular anomalies, and neural tube defects. Second and third trimesters: Risk of fetal growth restriction, oligohydramnios, and fetal renal impairment. Contraindicated in all trimesters. |
| Fetal Monitoring |
■ FDA Black Box Warning
Sulfonamides have been associated with severe hypersensitivity reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, and agranulocytosis. Fatalities have occurred despite discontinuation of therapy.
| Serious Effects |
Hypersensitivity to sulfonamides, porphyria, severe hepatic or renal impairment, pregnancy at term, and nursing infants.
| Precautions | Hypersensitivity reactions, severe skin reactions, hematologic toxicity, renal impairment, photosensitivity, and glucose-6-phosphate dehydrogenase deficiency. |
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| Monitor maternal blood pressure, renal function, and electrolyte levels. Fetal monitoring includes serial ultrasound for growth and amniotic fluid index, and fetal heart rate monitoring. Assess for signs of fetal distress. |
| Fertility Effects | May reduce fertility in females due to hormonal disruption. Reversible upon discontinuation. In males, may cause reversible decreased spermatogenesis and reduced sperm motility. |