SULFAIR 10
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SULFAIR 10 (SULFAIR 10).
Bacteriostatic inhibitor of dihydropteroate synthase, blocking folic acid synthesis in susceptible bacteria.
| Metabolism | Primarily hepatic via acetylation and glucuronidation; metabolites are inactive. |
| Excretion | Renal excretion of unchanged drug (approximately 70-80%) and hepatic metabolism (20-30% as metabolites). Fecal elimination is minimal (<5%). |
| Half-life | Terminal elimination half-life of 8-12 hours in adults with normal renal function (CrCl >60 mL/min); extends to 20-30 hours in severe renal impairment (CrCl <30 mL/min), requiring dose adjustment. |
| Protein binding | Approximately 85-90% bound to albumin. |
| Volume of Distribution | 0.35-0.45 L/kg (moderate tissue distribution; primarily extracellular fluid). |
| Bioavailability | Oral: 70-80% (fasting); reduced by 20% with food. Intravenous: 100%. |
| Onset of Action | Oral: 1-2 hours; Intravenous: 15-30 minutes (time to therapeutic plasma concentration). |
| Duration of Action | 12-24 hours (dosing interval q12-24h depending on infection severity and renal function). Prolonged in hepatic impairment. |
5 mg orally once daily, taken at bedtime.
| Dosage form | SOLUTION/DROPS |
| Renal impairment | GFR ≥60 mL/min: no adjustment. GFR 30-59 mL/min: 2.5 mg once daily. GFR 15-29 mL/min: use alternative therapy. GFR <15 mL/min: contraindicated. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for use in pediatric patients. |
| Geriatric use | Initiate at 2.5 mg once daily; titrate cautiously due to increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SULFAIR 10 (SULFAIR 10).
| Breastfeeding | Both components excreted in breast milk. M/P ratio: sulfadoxine ~0.4, pyrimethamine ~0.3. Low levels unlikely to cause adverse effects in term, healthy infants; caution in G6PD-deficient or jaundiced infants; theoretical risk of kernicterus in premature or hyperbilirubinemic infants. |
| Teratogenic Risk | Sulfair 10 contains sulfadoxine and pyrimethamine. In first trimester: crosses placenta; associated with congenital malformations (neural tube defects, cardiovascular anomalies) due to antimalarial effects; advised only if benefit outweighs risk. In second/third trimester: risk of hemolytic anemia in G6PD-deficient fetuses; kernicterus theoretically possible in third trimester due to bilirubin displacement; avoid near term. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to sulfonamides or any component; porphyria; megaloblastic anemia due to folate deficiency; pediatric patients <2 months of age; pregnancy at term and nursing mothers.
| Precautions | May cause hypersensitivity reactions including Stevens-Johnson syndrome; caution in renal impairment, hepatic impairment, glucose-6-phosphate dehydrogenase deficiency; monitor for crystalluria. |
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| Fetal Monitoring | Maternal: CBC with platelets, liver function tests weekly during treatment. Fetal: ultrasound for neural tube defects if exposure in first trimester; monitor for jaundice, hemolysis in neonate. |
| Fertility Effects | No known direct effects on fertility; untreated malaria may impair fertility and increase pregnancy complications; treatment of malaria may preserve fertility. |