Sodium aminosalicylate is an anti-tuberculosis drug, specifically a second-line agent used in the treatment of multidrug-resistant tuberculosis (MDR-TB). It is a bacteriostatic agent that acts as a competitive antagonist of para-aminobenzoic acid (PABA) in the folate synthesis pathway of Mycobacterium tuberculosis. It is almost exclusively used as part of a combination regimen to prevent resistance.
Adult: 8-12 grams per day, administered in 2-3 divided doses. The 800mg tablet strength typically requires 10-15 tablets daily (e.g., 4g every 8 hours). Dose is weight-based: 200-300 mg/kg/day, not to exceed 12g/day.
Note: Administer with or immediately after meals to minimize gastric irritation. Tablets should be swallowed whole with a full glass of water. Do not crush or chew. Doses should be evenly spaced. Can be dispersed in fruit juice or yogurt if swallowing multiple tablets is difficult, but must be consumed immediately.
Sodium aminosalicylate is a structural analog of para-aminobenzoic acid (PABA). It competitively inhibits the bacterial enzyme dihydropteroate synthase (DHPS). This inhibition blocks the incorporation of PABA into dihydrofolic acid, a precursor of folic acid. Since Mycobacterium tuberculosis cannot utilize preformed folic acid from the host, this disruption of folate synthesis leads to bacteriostatic inhibition of mycobacterial growth and replication.
Pregnancy: Category C: Animal studies show risk, human data limited. Use only if potential benefit justifies potential fetal risk. Should be used as part of a required MDR-TB regimen under specialist supervision. Folate supplementation is advised.
Driving: Unlikely to affect ability to drive or operate machinery. However, dizziness or headache may occur rarely.
| Rifampicin | May decrease serum levels of sodium aminosalicylate due to increased hepatic metabolism. | Moderate |
| Isoniazid | Concurrent use may increase risk of hepatotoxicity. PAS may increase INH levels. | Moderate |
| Digoxin | PAS may reduce digoxin absorption from the GI tract, decreasing its efficacy. | Moderate |
| Vitamin B12 | PAS can impair absorption of vitamin B12, potentially leading to deficiency and megaloblastic anemia. | Moderate |
| Warfarin | May potentiate the anticoagulant effect by displacing warfarin from protein binding sites and affecting vitamin K metabolism. | Major |
| Methotrexate | Increased risk of hematological toxicity due to synergistic folate antagonism. | Major |
| Probenecid | May decrease renal excretion of PAS, increasing risk of toxicity. | Moderate |