Comparative Pharmacology
Head-to-head clinical analysis: INH versus SODIUM P A S.
Peer-Reviewed Evidence
Head-to-head clinical analysis: INH versus SODIUM P A S.
INH vs SODIUM P.A.S.
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
INH inhibits InhA, an enoyl-acyl carrier protein reductase involved in mycolic acid synthesis, essential for the mycobacterial cell wall. It also disrupts NAD and NADH metabolism via the KatG-activated isonicotinoyl-NAD adduct.
Sodium P.A.S. (para-aminosalicylate) inhibits folic acid synthesis in Mycobacterium tuberculosis by competing with para-aminobenzoic acid, thereby suppressing bacterial growth.
300 mg orally once daily (or 15 mg/kg orally once daily, up to 300 mg total) for active tuberculosis; for latent tuberculosis, 300 mg orally once daily or 900 mg orally twice weekly under directly observed therapy.
4 g orally three times daily (total 12 g/day). For intravenous administration, 4 g (10 mL of 40% solution) diluted in 250 mL of 5% dextrose or normal saline infused over 2-3 hours three times daily.
None Documented
None Documented
Fast acetylators: 0.5-1.5 hours; slow acetylators: 2-4 hours. Clinically, slow acetylators have higher risk of peripheral neuropathy and hepatotoxicity.
0.5–1 hour (normal renal function); prolonged to ≥10 hours in renal impairment (requires dose adjustment).
Renal: 75-95% as unchanged drug and metabolites (including acetylisoniazid, isonicotinic acid). Biliary/fecal: minor (<5%).
Primarily renal (80-90% as unchanged drug) via glomerular filtration and tubular secretion; biliary/fecal ≤10%.
Category C
Category C
Antitubercular Agent
Antitubercular Agent