Isoniazid

**Mohsen Nabil * Admin** الأحد نوفمبر 13, 2011 12:55 am

]Isoniazid (INH)

Mechanism of action

Bacteriostatic @low conc. Vs resting bacteria

Bactericidal @high conc. Vs actively growing bacteria.

inhibit mycolic acid synthesis

suppress bacterial respiration

Pharmacokinetics

Absorbed orally & parentally

Metabolized in liver by
acetylation

Excreted mainly in urine
Diffuse in to all body fluids &tissues

T1/2 : 1-3 hrs

Antibacterial spectrum

Effective Vs
intra & extra cellular organisms

Clinical uses

Mycobacterial infections with pyridoxine to avoid neuropathy

Latent tuberculosis in pts with +ve tuberculin test

Prophylaxis Vs active TB

N.B... (we can use (INH) as a single therapy only in prophylactic the recurrence of active TB)

Adverse effects

Peripheral neuritis &CNS toxicity
....so , we give Vit B6

allergic reaction
Hepatitis

Gastric upset (N.V.D)

Haemolytic anaemia especially in pt with G6PD
Enzyme inhibitor

Potent enzyme inhibitor