5 (Student Presentation) - Anti tuberculosis: Isonicotinic Acid Hydrazide

Question 1

MoA of Drug to TB

Answer 1

Prodrug (activated by catalase-peroxidase KatG) –> Cleave INH’s hydrazide group –> isonicotinoyl radical formed –> react with NAD+ to form INH-NAD adduct –> inhibit enzyme reaction in cell wall –> lipid accumulation –> inhibit mycobacterium mycolic acid production –> interfere cell wall synthesis –> cell death of M. tuberculosis

Question 2

Drug Pharmacokinetics

Answer 2

Absorption: Reduced when administered together with sugar or following food intake

Distribution: Widely to all fluids and tissues

Metabolism: N-acetyl isoniazid (AcINH) –> 50-90% metabolised –> major

Excretion: Primarily in the urine (80%)

Question 3

Common side effects

Answer 3

GIT disturbances, rash, and peripheral neuropathy

Question 4

Side effect management

Answer 4

Leg burning sensation: Take pyridoxine 100 mg/day

Jaundice: Stop intake

Nausea, confusion (heart failure probability): Stop intake, check for heart function + prothrombin time