Anti-Mycobacterial Agents Flashcards
Mycobacteria important characteristics (4)
MYCOLIC ACID in cell wall
ACID FAST STAINING
INTRACELLULAR - replicate in macrophages
Generally SLOW GROWING
Latent TB
INACTIVE, non replicating tubercle bacilli
NORMAL CXR
NEGATIVE SPUTUM SMEARS/CULTURES
Not infectious - not a case of TB
Active TB
ACTIVELY replicating tubercle bacilli
ABNORMAL CXR
SMEARS AND SPUTUM POSITIVE
SYMPTOMS POSITIVE
Mycobacterium avium COMPLEX
M avium
M intracellulare
through contaminated food or water
may be disseminated
typically associated with IMMUNOCOMPROMISED
Active TB Recommended regimen
Initial phase - Rifampin, Isoniazid, Pyrazinamide, Ethambutol (RIPE) daily for 8 weeks
Continuation phase - Isoniazid and RIfampin daily for 18 weeks (or could do twice weekly)
Latent TB typical drug?
Isoniazid
6 or 9 month regimens
Isoniazid MOA
delivered as?
Use for TB?
INHIBITS MYCOLIC ACID SYNTHESIS
pro-drug - activated by bacteria
both latent and active infections
Resistance to Isoniazid associated with? (2)
mutations in Kat G gene
Overexpression of Inh A protein
Two major adverse effects with isoniazid?
Hepatitis
Peripheral neuropathy
Rifamycins MOA
inhibits RNA synthesis
BINDS BACTERIAL DNA-DEPENDENT RNA POLYMERASE
bactericidal for mycobacteria
Rifampin resistance associated with
point mutations in bacterial RNA polymerase
Rifampin adverse effects
GI disturbances
Neurological
hepatitis
Harmless red-orange color of urine, sweat, feces, etc.
Rifampin effect on cytochrome p450
Drug-drug interactions?
What can be substituted?
INDUCER
INCREASES METABOLISM OF ANTI-RETROVIRALS
Rifabutin
Pyrazinamide MOA
Used almost exclusively in?
not really known - inhibition of mycolic acid synthesis
pro-drug converted to active form by bacteria
COMBINATION THERAPY
Pyrazinamide resistance?
pyrazinamidase enzyme mutations
