PHCY 402 Test 3 Antibiotics
Study Guide @ 2024
what is the MOA of Ansamycins?
What is the common mode of resistance? - Answer inhibits the Bacterial RNA
polymerase to block transcription of dna
- resistance is aquired commonly by a mutation in the rna polymerase
what toxicity is associated with ansamycins and what drug interactions do they have? -
Answer - rarely toxic, liver toxicity espcially in those with preexisting problems
- induce 450 enzymes
What is a major counseling point for all ansamycins? - Answer - they change urine, stool,
sweat, and tears red / organge
What drug is 1st line for TB? who should not use this drug as 1st line? - Answer rafampin
***as long as not on protease inhibitor
Rifampin:
- what is it used to treat? what is it first line for?
- what are major counseling points for it?
- why cant this drug be used in aids paitents? - Answer - used to treat TB and
mycobacterium leprae - first line for both treatments
- counsel on class effects and rifampin gives flu like symptoms when take intermittently -
no missing doses
- this drug has major drug interactions with protease inhibitors --> gets into a negative
feed back loop with it
rifabutin:
- when is this a first line drug?
- what is an advantage of it?
-side effects? - Answer - first line in TB for those on protease inhibitors and for
mycobacterium avium complex
- this drug is good for AIDS patients because it has the lease side effects on p450s
, - polymyaglia, arthralgia, decreased granulocytes, and uveitis
Which ansamycin has the best activity on TB? - Answer Rifapentine
What are some major side effects of rifapentine? what can it not be used for? - Answer -
causes hyperuricemia and gout
- not for MAC treatment bc less activity than rifabutin
what is rifaximin used to treat? (4 things)
what is it not used for?
what is a big advantage for this drug? - Answer - used for traveler's diarrhea / e. coli,
IBS, Hepatic encephalopathy, PMC
- not used for mycobacterium (TB)
- has little and low effects on p450s
what is considered the '1st generation' fluoroquinolone? - Answer nalidixic acid served
as the lead compound for quinolones
What is the MOA for quinolones? are they static or cidal? - Answer They inhibit DNA
replication by blocking bacterial DNA gyrase and topoisomerase 2
- these are cidal drugs
What does the fluorine substitution on quinolones do for the drug? - Answer - this was
put at the sixth position to increase membrane penetration and to increase the potency
by 100x
What is the black box warning for quinolones? why does this happen? - Answer warning
for increased risk of tendinitis and tendon rupture in all ages. this risk is increased when
the person is over 60, taking corticosteroids, or has had an organ transplant.
- may exagerate myasthenia gravis
- moa is unclear but:
mitochondria release of ROS and decreased magnesium, effects on the MMP, and
increase expression of MMP-2 to degrade collagen
What kinds of toxicity do quinolones display? (there are 6) - Answer 1. cartilage toxicity
and joint swelling
2. tendinopathy BBW
3. neurotoxic
Study Guide @ 2024
what is the MOA of Ansamycins?
What is the common mode of resistance? - Answer inhibits the Bacterial RNA
polymerase to block transcription of dna
- resistance is aquired commonly by a mutation in the rna polymerase
what toxicity is associated with ansamycins and what drug interactions do they have? -
Answer - rarely toxic, liver toxicity espcially in those with preexisting problems
- induce 450 enzymes
What is a major counseling point for all ansamycins? - Answer - they change urine, stool,
sweat, and tears red / organge
What drug is 1st line for TB? who should not use this drug as 1st line? - Answer rafampin
***as long as not on protease inhibitor
Rifampin:
- what is it used to treat? what is it first line for?
- what are major counseling points for it?
- why cant this drug be used in aids paitents? - Answer - used to treat TB and
mycobacterium leprae - first line for both treatments
- counsel on class effects and rifampin gives flu like symptoms when take intermittently -
no missing doses
- this drug has major drug interactions with protease inhibitors --> gets into a negative
feed back loop with it
rifabutin:
- when is this a first line drug?
- what is an advantage of it?
-side effects? - Answer - first line in TB for those on protease inhibitors and for
mycobacterium avium complex
- this drug is good for AIDS patients because it has the lease side effects on p450s
, - polymyaglia, arthralgia, decreased granulocytes, and uveitis
Which ansamycin has the best activity on TB? - Answer Rifapentine
What are some major side effects of rifapentine? what can it not be used for? - Answer -
causes hyperuricemia and gout
- not for MAC treatment bc less activity than rifabutin
what is rifaximin used to treat? (4 things)
what is it not used for?
what is a big advantage for this drug? - Answer - used for traveler's diarrhea / e. coli,
IBS, Hepatic encephalopathy, PMC
- not used for mycobacterium (TB)
- has little and low effects on p450s
what is considered the '1st generation' fluoroquinolone? - Answer nalidixic acid served
as the lead compound for quinolones
What is the MOA for quinolones? are they static or cidal? - Answer They inhibit DNA
replication by blocking bacterial DNA gyrase and topoisomerase 2
- these are cidal drugs
What does the fluorine substitution on quinolones do for the drug? - Answer - this was
put at the sixth position to increase membrane penetration and to increase the potency
by 100x
What is the black box warning for quinolones? why does this happen? - Answer warning
for increased risk of tendinitis and tendon rupture in all ages. this risk is increased when
the person is over 60, taking corticosteroids, or has had an organ transplant.
- may exagerate myasthenia gravis
- moa is unclear but:
mitochondria release of ROS and decreased magnesium, effects on the MMP, and
increase expression of MMP-2 to degrade collagen
What kinds of toxicity do quinolones display? (there are 6) - Answer 1. cartilage toxicity
and joint swelling
2. tendinopathy BBW
3. neurotoxic
