Drugs Used In Tuberculosis - Second line Agents

on 19.1.08 with 0 comments



Second line drugs are less effective, more toxic and costlier.

Para-Amino Salicylic Acid (PAS)
  • Second line or reserve drug against Mycobacterium Tuberculosis
  • Structurally similar to Sulfonamides and acts through a similar mechanism.
  • Tuberculostatic.

Pharmacokinetics
  • Well absorbed orally
  • Poor concentration in the CSF
  • Metabolised in the liver by acetylation

Interactions
  • PAS reduces the absorption of Rifampicin
  • Competetively inhibits the acetylation of Isoniazid

USE
  • Reserve drug for the management of Multi Drug Resistant Tuberculosis

Adverse
  • Similar to Sulpha drugs, Including rashes, steven-johnson syndrome, crystalluria etc.

Ethionamide
  • Structurally similar to Isoniazid
  • Bacteriostatic
  • Effective against both Intacellular and extracellular bacilli
  • Well absorbed orally, metabolized in the liver and excreted in urine.

Cycloserine
  • Inhibits bacterial cell wall synthesis
  • Bacteriostatic
  • Well absorbed orally, crosses the Blood brain barrier and attains a good concentration in the CSF
  • Main adverse effects on the CNS - Headache, confusion, psychosis, depression and suicidal ideation.

Newer anti-tubercular Agents - Only used for treatment of MDR - TB
  • Newer Macrolides
  • Fluoroquinolones
  • Rifabutin
  • Rifapentin

Rifabutin
  • Derivative of Rifampicin
  • Preferred over rifampicin in treatment of tuberculosis in HIV patients on Protease inhibitors as it induces the microsomal enzymes to a lesser extent
  • Used in Mycobacterium Avium-Complex in combination with clarithromycin and Ethambutol.

Category: Pharmacology Notes

POST COMMENT

0 comments:

Post a Comment

Newer Post
Older Post
Subscribe to: Post Comments (Atom)