SODIUM AMINOSALICYLATE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).

How it works

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.

What the body does with it

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).

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).

Breastfeeding	Excretion into breast milk is unknown; due to potential for serious adverse reactions in nursing infants (e.g., hypersensitivity, gastrointestinal disturbance), decision should be made to discontinue nursing or the drug, taking into account importance of drug to mother.
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.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to aminosalicylic acid or any component; severe renal impairment (CrCl < 10 mL/min).

Clinical Precautions

Precautions

May cause hepatotoxicity, hypersensitivity reactions (fever, rash, eosinophilia), gastrointestinal intolerance, and crystalluria. Monitor liver function tests and renal function periodically.

Clinical Tips & Counseling

Drug interactions

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SODIUM AMINOSALICYLATE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).

How it works

What the body does with it

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).

Classification & Brands

Dosing & administration

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.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SODIUM AMINOSALICYLATE (SODIUM AMINOSALICYLATE).

Breastfeeding	Excretion into breast milk is unknown; due to potential for serious adverse reactions in nursing infants (e.g., hypersensitivity, gastrointestinal disturbance), decision should be made to discontinue nursing or the drug, taking into account importance of drug to mother.
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.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

Hypersensitivity to aminosalicylic acid or any component; severe renal impairment (CrCl < 10 mL/min).

Clinical Precautions

Precautions

May cause hepatotoxicity, hypersensitivity reactions (fever, rash, eosinophilia), gastrointestinal intolerance, and crystalluria. Monitor liver function tests and renal function periodically.

Clinical Tips & Counseling

Drug interactions

Loading safety data…