Mechanisms of Action Flashcards
what inhibits cell wall synthesis (bactericidal)?
Penicillin, amoxicillin, cephalexin
What inhibits protein synthesis (bacteriostatic)?
azithromycin
antifungals, such as __________, inhibit a CYP450 enzyme, which prevents the production of __________
fluconazole
ergosterol
Bacteria can resist antibiotics by preventing access to the _____, _____ the antibiotic, ______ the antibiotic, or rapid ______ of the antibiotic
antibiotic
degrading the antibiotic
altering the antibiotic
extrusion of the antibiotic
beta-lactamases can ________ the antibiotic and has a role in antibiotic resistance
disable
carbapenams are highly _______ to hydrolysis by penicilinases. often given to very ill patients
resistant
target proteins can be disguised, which occurs in _________ and penicillin binding proteins
MRSA
penetration of the drug is deterred only in _______ _______ species (because drug has to enter through the porins in the outer cell wall)
gram negative
discharge is a form of antibiotic resistance, when a _____ _____ transports antibiotic back across the outer membrane of out of the bacteria
proton pump
most beta-lactams end in -____, -____, or start with ceph-
- cillin
- penem
beta-lactams bind to penicillin-binding protein at the active site and prevent _________ (peptidoglycan chains require this to be strong)
crosslinking
the most prevalent mechanisms for antibiotic resistance are inactivation of antibiotic by ________ and modification of ______ (low affinity to bind to antibiotic)
B-lactamase
penicillin-binding proteins
gram _______ are most susceptible to beta lacams
gram positive (rely on the peptidoglycan chains in their cell wall)
mycoplasma don’t have a cell wall (no peptidoglycan to inhibit), so _______ won’t work
beta latams
the three general categories of penicillin are:
penicillins
antistaphylococcal penicillins
extended-spectrum penicillins
penicillins are polar, so ______cellular concentrations will be higher than _____cellular
extracellular
intracellular
penicillin is rapidly excreted by the kidneys in its active form, so it’s great for _____
UTIs
penicillin V have the greatest activity against ________, ______, and non-beta-lactamse anaerobes
gram positive
gram negative cocci
penicillin V are not effective against gram _____ ______
negative rods
resistance is high for PCNs, so seldom used as ______ treatment
empiric
penicillin V (oral) treats mild to moderate infections because of its ______________.
poor bioavailability
Downside of penicillin V is its dosing of ______ a day
4 times
penicillin VK is combined with _______ so it is protected against _________
potassium
gastric acid
penicillin should be given ______ food
without
GI (nausea, vomiting) and ________
hypersensitivy (skin most common)
bacteriostatic antibiotics (tetracyclines) may lead to antagonism of _______ activity of penicillin V
bactericidal
OCPs are excreted by liver, estradiol is reabsorbed. With penicillin, this may _____ efficacy of OCPs
reduce
antistaphococals are specific for targeting ______ (only gram positive!)
staph
amoxicillin can be given 2-3 times a day, versus 4. Better _____, greater ______
tolerated
better bioavailability
the most active of the beta-lactams agains strep infections are _______ (moderate against gram neg)
amoixicillin
________ are poor against staph
amoxicillin
absorption of _______ isn’t affected by food
amoxicillin
amoxicilin is excreted ______ in the ______
unchanged
urine
continue treatment with penicillin if the rash is ______, which is common with amoxicillin
morbilliform (looks like measles)
amoxicillin 500 mg #20
take 2 tab PO daily x 10 days with food
example drug card
_____ have synergistic activity with aminoglycosides
penicillin VK, amoxicillin
beta-lactamase inhibitors can be added to amoxicillin in order to ______ the activity to include gram ____ bacteria
extend
gram negative
the 3 beta-lactamase inhibitors are:
clavulanate
sulbactam
tazobactam
amoxicillin with clavulanate is a _______ synthesis inhibitor with a _______ inhibitor
cell wall
beta lactamase
clavuanic irrersibly binds ____ _____ produced by a number of gram neg and positive.
beta lactamases
beta lactamases are not active against antibiotics, but they ________ the penicillins spectrum of activity
increase
Amox-Clav #28
875 mg 1 tab PO BID X 14 days
Cephalexin #40
250 mg 1 tab PO QID x 10 days
drug example
the are ____ generations of cephalosporins. The higher the generation, the ____ the gram negative coverage improves
5
higher (gram positive coverage decreases)
cephalosporins have the greatest activity against ____ ____ and least againast gram ____
gram positive
gram negative
_____ is very active against gram-positive cocci, but not against MRSA
cephalexin
2nd generation cephalosporins are _____ as 1st generation, with addition of some _______ anaerobes
heterogeneous
added gram negative
3rd generation has expanded gram _____ coverage, but decreased gram positive coverage
negative
4 generation cephalosporins is helpful with ______ and _____, also covers staph auras, hemophilus, neisseria
enterobacter
pseudomonas
5th generation cephalosporins has improved gram _____ activity (good for MRSA!)
positive
all beta-lactams lack activity against _____ and ____
mycoplasma and chlamydia
only ____ generation cephalosporin is anti mRSA
5th
_______ have higher affinity to PBP (more potent)
carbapenems
carbapenems are commonly used in ______ and the ICU
hospitals
imipenem is always paired with _______, because it would otherwise be inactivated in the kidney by enzymes. Cilastatin inactivates them.
Cilastatin
Monobactams have a very ______ spectrum; only bind to PBP in _____, _____
PBP
enterobactera
Pseudomonas aeruginosia
__________ penicillin is works against pesudomonas aeurginosa. Not good against staph.
antipseudomonal
_______ is commonly prescribed for otitis media, sinusitis, skin infections, pneumonia
amoxicillin and clavulanate (Augmentin)
if there are no beta-lactamases, you should not prescribe a drug with ________ bc it won’t be beneficial
clavulanic acid
