Antitubercular Agents Flashcards
Mechanism of Action of Streptomycin
inhibits CHON synthesis, irreversibly inhibit bacterial protein synthesis and binds to 30s subunit, causing a misreading of tRNA then leaving the bacteria unable to synthesize proteins
Mechanism of Action of Rifampin
S. mediterranei
inhibits RNA polymerase, inhibits DNA-dependent RNA polymerase activity by forming a stable complex w/ the enzyme
-suppresses initiation of RNA synthesis and leads to cell death
Mechanism of Action of Para Aminosalicylic Acid
Competitive inhibitor for PABA
Mechanism of Action of Ethionamide
Structural analogue of isoniazid
Mechanism of Action of Isoniazid
inhibits cell wall synthesis
First antibiotic for TB
Streptomycin
Most active agent and Enzyme inducer
Rifampin
S. mediterranei
For isoniazid resistant TB
Ethionamide
First line drug for short term tx
Pyrazinamide (Pyrazinecarboxamide)
Active form of Pyrazinamide
Pyrazinoic acid
First line
Isoniazid
Isonicotinic acid hydrazide
Basic red dye for leprosy, including dapsone resistant forms
Clofazimine
Combined with other agents (resistance develops rapidly)
Pyrazinamide (Pyrazinecarboxamide)
Streptomyces: S. orchidaceus, S. garyphalus, S. Lavendulus
Cycloserine
Streptomyces capreolus
Capreomycin
Adverse effects of Streptomycin
Ototoxicity, nephrotoxicity
Adverse effects of Rifampin
Reddish secretions
+ INH or ethambutol–> higher hepatotoxicity
Adverse effects of Clofazimine
Hyperpigmentation
Adverse effects of Para Aminosalicylic Acid
Severe GI irritation
Adverse effects of Ethionamide
Hepatotoxicity, Peripheral neuritis