TRIPLE SULFOID
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIPLE SULFOID (TRIPLE SULFOID).
Triple sulfoid (sulfadiazine, sulfamethazine, sulfamerazine) competes with para-aminobenzoic acid (PABA) to inhibit dihydropteroate synthase, blocking bacterial folate synthesis.
| Metabolism | Primarily hepatic via acetylation and glucuronidation; CYP450 involvement not significant. |
| Excretion | Renal: ~70% as unchanged drug; hepatic metabolism: ~20%; fecal: ~10% |
| Half-life | 10-12 hours in normal renal function; prolonged to 24-48 hours in severe renal impairment (CrCl <30 mL/min) |
| Protein binding | 85-90% bound to albumin |
| Volume of Distribution | 0.2-0.3 L/kg, indicating limited extravascular distribution |
| Bioavailability | Oral: 70-80% (first-pass metabolism reduces from ~100%) |
| Onset of Action | Oral: 2-4 hours; Intravenous: 15-30 minutes |
| Duration of Action | Oral: 12 hours; Intravenous: 6-8 hours |
| Molecular Weight | 214.2 |
2 tablets orally every 6 hours for 10-14 days; each tablet contains sulfadiazine 270 mg, sulfamerazine 270 mg, and sulfamethazine 270 mg.
| Dosage form | TABLET |
| Renal impairment | CrCl 30-50 mL/min: interval every 8-12 hours; CrCl 15-29 mL/min: interval every 12-24 hours; CrCl <15 mL/min: contraindicated. |
| Liver impairment | Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50% or extend interval; Child-Pugh Class C: contraindicated. |
| Pediatric use | Children >2 months: 25-50 mg/kg/dose (based on total sulfonamide content) orally every 6 hours; maximum 2 g/day. |
| Geriatric use | Start at lower end of dosing range; monitor renal function and adjust per renal adjustment; avoid in severe renal impairment. |
| 1st trimester | Avoid use during first trimester due to potential teratogenic effects associated with sulfonamides, including neural tube defects and cardiovascular malformations. Sulfonamides may interfere with folic acid metabolism. |
| 2nd trimester | Use only if clearly needed. Sulfonamides can compete for bilirubin binding sites on albumin, increasing the risk of kernicterus in the neonate if administered near term. In second trimester, risk is lower but caution advised. |
| 3rd trimester | Contraindicated in third trimester, especially after 36 weeks, due to risk of neonatal hyperbilirubinemia and kernicterus. Sulfonamides are known to displace bilirubin from albumin and may cause hemolytic anemia in G6PD-deficient infants. |
Clinical note
Comprehensive clinical and safety monograph for TRIPLE SULFOID (TRIPLE SULFOID).
| Placental transfer | Sulfonamides, including the components of Triple Sulfoid (sulfabenzamide, sulfacetamide, sulfathiazole), cross the placenta readily, achieving fetal serum concentrations approximately 50-80% of maternal levels. Placental transfer is well-documented. |
■ FDA Black Box Warning
WARNING: FATALITIES ASSOCIATED WITH SULFONAMIDES HAVE OCCURRED DUE TO STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS, FULMINANT HEPATIC NECROSIS, AGRANULOCYTOSIS, APLASTIC ANEMIA, AND OTHER BLOOD DYSCRASIAS.
| Serious Effects |
Known hypersensitivity to sulfonamides or any component of Triple SulfoidSevere renal impairment (e.g., creatinine clearance <30 mL/min)Severe hepatic impairmentPorphyria (sulfonamides may precipitate acute attacks)Third trimester of pregnancy (risk of kernicterus)Infants less than 2 months of age (except for treatment of congenital toxoplasmosis)Breastfeeding infants with G6PD deficiency or hyperbilirubinemiaHistory of drug-induced Stevens-Johnson syndrome or toxic epidermal necrolysis
| Precautions | Hypersensitivity reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis; hematologic toxicity including agranulocytosis and aplastic anemia; hepatotoxicity; renal damage due to crystalluria; photosensitivity; hemolysis in glucose-6-phosphate dehydrogenase (G6PD) deficiency. |
| Food/Dietary | Avoid high-protein diets and vitamin C supplements, as they can acidify urine and increase risk of crystalluria. Limit foods rich in purines (e.g., organ meats, anchovies) to reduce urate load. Maintain adequate caloric and fluid intake; no specific food restrictions other than ensuring acidic urine is avoided. Alkalinizing foods like citrus fruits may be beneficial. |
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| Breastfeeding |
| Small amounts of sulfonamides are excreted into breast milk. Avoid breastfeeding while taking Triple Sulfoid, especially in infants with G6PD deficiency, hyperbilirubinemia, or those who are premature or ill, due to the risk of kernicterus and hemolytic anemia. Alternative therapies are recommended. |
| Lactation Rating | L4 - Possibly Hazardous. May be used with caution if safer alternatives are not available, but close monitoring of the infant is required. |
| Teratogenic Risk | Triple sulfoid (a combination of sulfonamides) poses a teratogenic risk primarily due to sulfamethoxazole. First trimester: Association with neural tube defects, cardiovascular anomalies, and cleft palate (OR 2.1-3.3). Second trimester: Risk of kernicterus if administered near delivery due to bilirubin displacement. Third trimester: Avoid after 32 weeks due to risk of neonatal hyperbilirubinemia and kernicterus. Overall, use only if benefit clearly outweighs risk. |
| Fetal Monitoring | Monitor complete blood count (CBC) for hemolytic anemia, leukopenia; liver function tests (LFTs); renal function (BUN, creatinine); urine analysis for crystalluria; bilirubin levels near term. Fetal ultrasound for structural anomalies if first-trimester exposure. |
| Fertility Effects | No established adverse effects on fertility in humans. Animal studies show no significant impact on reproductive performance. |
| Clinical Pearls | Triple sulfoid (sulfadiazine, sulfamerazine, sulfamethazine) is rarely used due to high risk of crystalluria and hypersensitivity. Ensure adequate urine output (at least 1500 mL/day) and alkalinization (pH >7.15) to prevent crystal nephropathy. Monitor for Stevens-Johnson syndrome, agranulocytosis, and photosensitivity. Not first-line; consider alternatives like TMP-SMX. |
| Patient Advice | Take each dose with a full glass of water and drink plenty of fluids throughout the day to prevent kidney crystals. · Avoid prolonged sun exposure; use sunscreen and protective clothing as this medication increases sun sensitivity. · Complete the full course even if feeling better; do not skip doses. · Report severe skin rash, fever, sore throat, easy bruising, or dark urine immediately. · This medication may reduce the effectiveness of oral contraceptives; use additional non-hormonal birth control. |