TB Meds Flashcards
is mycobacterium slow or fast growing?
Slow growing
What makes mycobacterium cell wall relatively impermeable to many antibiotics?
Mycolic acid
What primarily happens to mycobacteria?
Survive in the macrophages (another layer for antibiotic to get through)
How long are therapies for TB?
months
How is TB transmitted?
Airborne particles
What does isoniazid target?
Inhibits mycolic acid synthesis through the formation of :
reactive oxygen-radicals
isonicotinic acid
What type of antibiotic is isoniazid?
Bacteriostatic and bactericidal
When is isoniazid considering bactericidal?
When the mycobacterium is rapidly dividing
Does isoniazid have any cross resistance?
No because they have a different mechanisms
What are some AEs of Isoniazid?
Peripheral neuritis: pyridoxine deficiency
What should you prescribe along with Isoniazid?
Pyridoxine (B6)
What does isoniazid inhibit the metabolism of?
Phenytoin
What is a side effect of isoniazid that increases iwth rifampin or daily ETOH?
Hepatitis/ hepatotoxicity
What is the black box warning with isoniazid?
Severe and sometimes fatal hepatitis associated w/ isoniazid therapy may occur and even develop after many months of treatment
How does rifampin work?
Interact w/ DNA_dependent RNA polymerase
Which has a broader spectrum- INH or rifampin?
rifampin
What is rifampin effective against?
gram + and - organisms. Used prophylactically in individuals exposed to meningitis
What type antibiotic is rifampin?
Bactericidal
What does rifampin induce?
Its own meatbolism and meatbolism of oral contraceptives
How if rifampin eliminated?
feces, urine
What can happen to rifampin with tears?
Orange-red color tears
Besides changing color of fluids what are some AEs of rifamyins?
Minor- N/V
What type antibiotic is pyranzinamide?
bactericidal
What does pyrazinamide affect?
Mycolic acid biosyntehsis byt inhibiting fatty acid synthase
Where does pyrazinamide accumulate?
Macrophages, monocytes,
helps prolong therapy
What are some AEs of pyrazinamide?
liver injury
jaundice
check liver function tests
What type antibiotic is ethambutol?
bacteriostatic
What is an exception to the combing of bacteriostatic and bactericidal?
Ethambutol w/ other TB meds
such a slow growing organism that it doesn’t affect
What does ethambutol inhibit?
synthesis of polysaccharides and transfer mycolic acids to cell wall
What drug helps prevent more rifampin resistance for developing?
Ethambutol
What is the most important AE of ethambutol?
optic neuritis results in
diminished visual acuity
loss of red/ green discrimination
