Antibiotics Flashcards
How are most antibiotics cleared by the body?
renally excreted
what are some drugs that are not handled by the kidney and thus metabolized by the liver?
clindamycin erythromycin chloramphenicol metronidazole nafcillin
What is the MOA of penicillins?
cell wall synthesis inhibitors (bind to and inhibit PBP)
what are some mechanisms of resistance to penicillin?
beta-lacatamase sensitive
alteration in the PBP site
changes in the cell mb (change in porin function)
which type of penicillin is available only as an oral preparation?
penicillin V
What drug interacts with penicillin and will increase serum concentrations of it?
probenecid
What is the DOC for surgical prophylaxis?
Cefazolin (Ancef) 2g IV one hour before surgery
What is the DOC for N. gonorrhea coverage?
Ceftriaxone (Rocephin)
250 mg IM injection
What is the most active cephalosporin against P. aeruginosa?
Ceftazidime (Fortaz)
Why is Imipenem always combined with Cilastatin?
Imipenem is destroyed in the kidney; Cilastatin inhibits renal enzymes from degrading the imipenem
What does the Cockroft and Gault formula measure?
creatinine clearance
What is the Cockroft and Gault formula?
creatinine clearance = (140-age) x (weight in kg)/ (serum Cr x 72)
*if women, multiply by 0.85
you have to draw peaks & troughs when giving what type of antibiotics?
aminoglycosides
which (peak or trough) is dose-dependent? which is time-dependent?
peak- is dose dependent
trough- is time dependent
if peak is high and trough is normal, what would you do?
decrease the dose
if peak is normal and trough is low, what would you do?
decrease the time between doses
Which drugs are good against anaerobes?
Metronidazole (Flagyl)
Clindamycin (Cleocin)
what AE is associated with vancomycin? how would you avoid this
Red Man syndrome- give it over 45-60 min to prevent
What 3 aminoglycosides have indications for LE use?
gentamicin
tobramycin
amikacin
Which aminoglycoside has the best activity against Serratia?
Gentamicin
Which aminoglycoside is the most effective against P. aeruginosa?
tobramycin
Which aminoglycoside is used for infection caused by Gram (-) organisms resistant to gentamicin and tobramycin?
amikacin
what is the spectrum of activity of aminoglycisdes?
aerobic Gram (-) bacteria *is effective against staph and some strep but there are other drugs that are safer to use
What are some of the feared side effects of aminoglycosides?
nephrotoxicity- reversible
otoxoticity- IRREVERSIBLE
neuromuscular blockade
