SULFALOID
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SULFALOID (SULFALOID).
Sulfaloid is a sulfonamide antibiotic that inhibits bacterial dihydropteroate synthase, blocking folate synthesis and thereby nucleic acid production in susceptible bacteria.
| Metabolism | Primarily hepatic via acetylation and glucuronidation; metabolites are excreted renally. |
| Excretion | Renal: 70% (unchanged via glomerular filtration and tubular secretion); Biliary/fecal: 20% (conjugated metabolites); 10% metabolized in liver to inactive acetylated derivatives. |
| Half-life | Terminal elimination half-life: 6-8 hours in adults with normal renal function (ClCr >90 mL/min); prolonged to 12-20 hours in moderate renal impairment (ClCr 30-50 mL/min) and >30 hours in severe renal impairment (ClCr <30 mL/min). |
| Protein binding | 80-85% bound to serum albumin (primarily); minor binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.2-0.3 L/kg (approximate total body water); indicates distribution into extracellular fluid with minimal tissue penetration. |
| Bioavailability | Oral: 90-95% (rapidly absorbed from proximal small intestine); Topical: <5% (negligible systemic absorption). |
| Onset of Action | Oral: 30-60 minutes; Intravenous: 5-10 minutes; Topical: 1-2 hours for local antimicrobial effect. |
| Duration of Action | Oral/IV: 8-12 hours (bacteriostatic levels maintained with twice-daily dosing); Topical: 6-8 hours (reapplication recommended). |
| Molecular Weight | 250.27 |
500 mg orally every 12 hours for 7-10 days.
| Dosage form | SUSPENSION |
| Renal impairment | GFR 30-50 mL/min: 250 mg every 12 hours; GFR 15-29 mL/min: 250 mg every 24 hours; GFR <15 mL/min: 250 mg every 48 hours or after dialysis. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: 250 mg every 12 hours; Class C: not recommended. |
| Pediatric use | For children >2 years: 10 mg/kg orally every 12 hours, maximum 500 mg per dose for 7-10 days. |
| Geriatric use | Initial dose 250 mg orally every 12 hours; monitor renal function and adjust based on creatinine clearance. |
| 1st trimester | Contraindicated due to risk of kernicterus in neonates; sulfonamides displace bilirubin from albumin binding sites, potentially causing fetal neurotoxicity. |
| 2nd trimester | Use only if clearly needed; caution in later pregnancy due to possible neonatal jaundice and hemolytic anemia in G6PD-deficient fetuses. |
| 3rd trimester | Avoid near term (after 37 weeks) because of high risk of kernicterus and hemolytic anemia in newborns; sulfonamides can cause neonatal hyperbilirubinemia. |
Clinical note
Comprehensive clinical and safety monograph for SULFALOID (SULFALOID).
| Placental transfer | Sulfonamides readily cross the placenta, achieving fetal serum levels approximately 50-90% of maternal levels. Transfer is via passive diffusion, and the drug accumulates in fetal tissues including the liver and gallbladder. |
| Breastfeeding | Sulfonamides are excreted in breast milk in small amounts. Risk of kernicterus is theoretical but may be significant in premature infants or those with hyperbilirubinemia or G6PD deficiency. American Academy of Pediatrics considers sulfonamides compatible with breastfeeding in healthy full-term infants, but caution is advised. Monitor infant for jaundice, hemolysis, and rash. |
■ FDA Black Box Warning
Sulfonamides have been associated with severe adverse reactions including Stevens-Johnson syndrome, toxic epidermal necrolysis, and agranulocytosis. Fatalities have occurred. Avoid use in patients with known hypersensitivity to sulfonamides.
| Serious Effects |
Hypersensitivity to sulfonamides or any componentPorphyriaSevere hepatic or renal impairment (only if specifically noted for this sulfonamide)
| Precautions | Risk of severe cutaneous reactions (SJS/TEN), hematologic toxicity (agranulocytosis, aplastic anemia), hepatotoxicity, and renal toxicity. Monitor CBC, renal function, and hepatic function. Discontinue at first sign of rash or blood dyscrasia. |
| Food/Dietary | Avoid high-protein or acidic foods that may increase risk of crystalluria. Avoid alcohol (disulfiram-like reaction possible). Do not take with dairy products or calcium-fortified juices, as they may reduce absorption. |
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| Lactation Rating | L3 - Moderately Safe |
| Teratogenic Risk | Sulfaloid is contraindicated in pregnancy. First trimester: Associated with neural tube defects, cardiovascular malformations, and cleft palate due to folate antagonism. Second and third trimesters: Risk of kernicterus in neonates due to bilirubin displacement from albumin; sulfonamides cross the placenta and may cause hemolytic anemia in G6PD-deficient fetuses. |
| Fetal Monitoring | Monitor maternal CBC, liver function, and renal function. Assess for signs of hypersensitivity, hemolytic anemia, and crystalluria. Fetal monitoring includes ultrasound for neural tube defects (first trimester) and assessment of bilirubin levels at birth. Newborn should be observed for jaundice, hemolysis, and Kernicterus. |
| Fertility Effects | Sulfaloid may impair fertility in females by inhibiting folate metabolism, affecting ovulation. In males, sulfonamides may reduce sperm count and motility. Effects are dose-dependent and typically reversible upon discontinuation. |
| Clinical Pearls | Sulfaloid is a sulfonamide antibiotic. Ensure adequate hydration to prevent crystalluria. Monitor for hypersensitivity reactions, especially in patients with G6PD deficiency or sulfa allergies. Adjust dose in renal impairment (CrCl <30 mL/min). Avoid use in infants <2 months due to risk of kernicterus. |
| Patient Advice | Take with a full glass of water and drink plenty of fluids throughout the day to prevent kidney crystals. · Finish the entire course even if you feel better; do not skip doses. · Avoid sun exposure and use sunscreen; may cause photosensitivity. · Report any skin rash, fever, sore throat, or unusual bleeding immediately. · Do not take if you have a known allergy to sulfa drugs or if pregnant/nursing. |