Antimycobacterial drugs Flashcards
first line drugs for tuberculosis
rifampin
pyrazinamide
ethambutol
isoniazid
second line drugs for tuberculosis
rifabutin rifapentine fluoroquinolone capreomycine ethionamide amikacin kanamycin
ISONIAZID ROA
oral
parenterally
isoniazid MOA
inhibit synthesis of mycolic acid
activated by catalase-peroxidase encoded by KatG gene
resistance to isoniazid
mutation of the KatG gene
isoniazid bactericidal or bacteriostatic?
bactericidal
isoniazid indication
bactericidal - M. tuberculosis and M.kansasii
M. avium-intracellulare
LATENT TB
prevent TB in neonates and children in close contact
prophylaxis: if + for tuberculin, HIV+ and recent exposure
AE isoniazid
Hepatitis (age dependent)
Peripheral neuritis: drug induced pyridoxine deficiency (B6) (paresthesia, numb finger and toe)
RARE: toxic encephalopathy and hematologic; granulocytosis, anemia, thrombocytopenia
ETHAMBUTOL bactericidal or bacteriostatic?
bacteriostatic
ethambutol roa
orally (w other drugs TB and M. AI
ethambutol moa
inhibit arabinosyl transferase and synthesis of arabinogalactan for cell wall
ethambutol resistance
mutation in arabinosyl transferase
AE ethambutol
Optic neuritis
impaired green-red color discrimination (retrobulbar neuritis)
CI in children to young to assess visual activity)
hyperuricemia, GOUT
hepatitis, thrombocytopenia
Pyrazinamide bactericidal or bacteriostatic?
bactericidal
pyrazinamide moa
orally given for M.TB, given in combination with isoniazid, ethambutol and rifampin
pyrazinamide MOA
nicotinamide derivative, converted in mycobacteria to active metabolite pyrazinoic acid by pyrazinamidase
inhibit fatty acid synthesis and translation
pyrazinamide resistance
mutation in pyrazinamidase
pyrazinamide AE
arthralgia
hyperuricemia and gout
hematologic toxicity
hepatitis and increase in serum ion concentration
pyrazinamide contraindicated
in pregnant women
Rifampin - broad or narrow spectrum?
broad
rifampin ROA
oral/IV