SODIUM AMINOSALICYLATE
Clinical safety rating
cautionComprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).
Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).
Tuberculosis (second-line therapy, in combination with other antituberculous agents)
Sodium aminosalicylate inhibits folic acid synthesis in Mycobacterium tuberculosis by competing with para-aminobenzoic acid (PABA) for the enzyme dihydropteroate synthase, thereby blocking bacterial growth.
| Metabolism | Hepatic acetylation (N-acetyltransferase) and renal excretion of metabolites. |
| Excretion | Renal: >80% as metabolites (acetylated and free), with 50-60% as N-acetyl-4-aminosalicylic acid; biliary/fecal: <1%. |
| Half-life | 0.75-1.5 hours (parent drug); prolongs to 4-6 hours in renal impairment or with probenecid coadministration. Rapid acetylation phenotype reduces half-life by ~30%. |
| Protein binding | 50-60% bound to albumin; binding is saturable at high concentrations. |
| Volume of Distribution | 0.2-0.3 L/kg (distributes into total body water; low tissue penetration except inflamed pleural fluid and caseous granulomas). |
| Bioavailability | Oral: 90-100% (rapidly absorbed from GI tract); no parenteral formulation available. |
| Onset of Action | Oral: 1-2 hours (time to peak serum concentration); clinical effect (bacteriostatic) typically requires 4-8 weeks for sustained response in tuberculosis. |
| Duration of Action | 6-8 hours (bacteriostatic effect persists for dosing interval with TID/QID regimen; therapeutic duration for tuberculosis: 9-12 months in combination therapy). |
| Molecular Weight | 175.14 |
4 g orally three times daily (total daily dose 12 g) for tuberculosis treatment. Also available as 10 g in 250 mL for intravenous infusion over 5-6 hours, typically once daily.
| Dosage form | POWDER |
| Renal impairment | For GFR <30 mL/min: reduce dose to 4 g orally twice daily (total 8 g/day). For GFR <10 mL/min: administer 4 g orally once daily. No adjustment for GFR ≥30 mL/min. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: consider 50% dose reduction. Child-Pugh Class C: use with caution; consider further reduction or alternative therapy as pharmacokinetics are not well studied. |
| Pediatric use | Children: 150-300 mg/kg/day orally divided into 3-4 doses, not to exceed 12 g/day. Intravenous: 150-200 mg/kg/day as a continuous infusion or in divided doses. |
| Geriatric use | Start at lower end of dosing range (e.g., 4 g orally twice daily) due to age-related decline in renal function. Monitor renal function and adjust per GFR-based guidelines. Caution with hepatic impairment. |
| 1st trimester | Avoid due to teratogenic potential (similar to salicylates); case reports of congenital malformations. Use only if benefit outweighs risk. |
| 2nd trimester | Use with caution; monitor maternal and fetal effects. May interfere with maternal thyroid function. |
| 3rd trimester | Avoid in late pregnancy due to risk of premature closure of ductus arteriosus and neonatal complications (e.g., bleeding, pulmonary hypertension). |
Clinical note
Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).
| Placental transfer | Crosses the placenta; detectable in fetal serum and amniotic fluid. Degree similar to salicylate. |
| Breastfeeding | Excreted into breast milk in low amounts; potential for kernicterus in neonates, especially if premature or hyperbilirubinemic. Use only if essential; monitor infant for jaundice. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Limited data; animal studies show some teratogenicity at high doses; no adequate human studies; use only if clearly needed. Second and third trimesters: No specific known fetal risks; however, theoretical risk of kernicterus due to bilirubin displacement from albumin binding, though not confirmed with aminosalicylic acid. |
| Fetal Monitoring | Monitor liver function tests, renal function, and complete blood counts in the mother periodically. Assess for signs of hypersensitivity reactions. Fetal monitoring not specifically required but consider serial ultrasound for growth restriction if used in pregnancy. |
| Fertility Effects | No specific studies on fertility; animal studies have not shown impaired fertility. Theoretical potential for reversible male infertility due to folic acid antagonism, though not well-documented. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to aminosalicylates or salicylatesSevere renal impairment (GFR <30 mL/min)Severe hepatic failure
| Precautions | May cause hepatotoxicity, hypersensitivity reactions (fever, rash, eosinophilia), gastrointestinal intolerance, and crystalluria. Monitor liver function tests and renal function periodically. |
| Food/Dietary | Take with or after meals to minimize gastrointestinal irritation. Avoid alcohol due to increased risk of hepatotoxicity and GI upset. No specific food interactions; but a low-fat diet may help reduce GI side effects. |
| Clinical Pearls | Sodium aminosalicylate (PAS) is a bacteriostatic agent used in combination therapy for multidrug-resistant tuberculosis. Administer with or after meals to reduce gastrointestinal upset. Monitor liver function tests and renal function periodically. Watch for hypersensitivity reactions, including fever, rash, and eosinophilia. Use with caution in patients with glucose-6-phosphate dehydrogenase deficiency due to risk of hemolytic anemia. |
| Patient Advice | Take this medication with or after food to reduce stomach upset. · Do not skip doses or stop taking this medication without consulting your doctor. · Report any signs of allergic reaction such as rash, fever, or swelling. · Avoid alcohol while taking this medication. · Keep all appointments for blood tests to monitor liver and kidney function. · Contact your doctor if you experience nausea, vomiting, abdominal pain, or yellowing of skin or eyes. |
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