Meta-aminosalicylic acid (also known as p-aminosalicylic acid or PAS) is a chemical compound that belongs to the class of aminosalicylates. It is primarily used as an antibiotic medication in the treatment of tuberculosis, particularly when other first-line drugs have proven ineffective or the bacteria show resistance.
Meta-aminosalicylic acid is an aromatic carboxylic acid characterized by a para-substituted amino group (-NH2) and a hydroxy group (-OH) on the benzene ring. Its chemical formula is C7H7NO3, with a molecular weight of approximately 153.14 grams per mole. Structurally, it is similar to salicylic acid, but its substitution pattern enhances its antimycobacterial properties.
As an antibiotic, meta-aminosalicylic acid exhibits bacteriostatic activity against Mycobacterium tuberculosis by interfering with the mycolic acid synthesis, essential for the integrity of the bacterial cell wall. By inhibiting a specific enzyme involved in this process, it hampers the growth and replication of the bacteria, eventually leading to their elimination.
Meta-aminosalicylic acid is usually administered orally as a tablet or capsule after meals. It is rapidly absorbed by the gastrointestinal tract and distributed throughout the body. The medication is mainly excreted through the kidneys, and dose adjustments may be required in patients with impaired renal function.
Although generally considered safe, meta-aminosalicylic acid may cause adverse effects such as gastrointestinal disturbances (nausea, vomiting, diarrhea), skin rashes, and fever. Regular monitoring and caution are necessary to manage any potential drug interactions and ensure optimal therapeutic outcomes.
