antibiotics pharmacology 1 Flashcards
what is the smallest organism?
bacteria.
a substance which destroys or inhibits the growth of microorganisms?
antimicrobial.
a substance that destroys or inhibit the growth or action of microorganisms on living tissue.
antiseptic.
a substance produced by or derived from microorganism and able to inhibit or kill another microorganism.
antibiotic.
lowest concentration that results in inhibition of visible growth?
minimum inhibitory concentration (MIC).
lowest concentration that kills 99.9% of the original inoculum.
minimum bactericidal concentration (MBC).
MBC and MIC, are which type of testing?
antibiotic susceptibility testing (in vitro).
Antibiotics are classified based on what?
1- mechanism of action.
2- chemical structure.
3- spectrum of activity.
List the mechanisms of action of bacteriostatic?
1- inhibition of DNA gyrase and RNA polymerase.
2- inhibition of protein synthesis.
3- inhibition of folic acid metabolism.
Give an example of bacteriostatic antibiotics that inhibit DNA gyrase and RNA polymerase?
Quinolones and Rifampin.
Give an example of bacteriostatic antibiotics that inhibit protein synthesis?
Tetracyclines, erythromycin, aminoglycosides and chloramphenicol.
Give an example of bacteriostatic antibiotics that inhibit folic acid metabolism?
Trimethoprim and sulfonamides.
What is the mechanism of action of bactericidal antibiotics?
Inhibition of cell wall synthesis.
Give an example of bactericidal antibiotics that inhibit cell wall synthesis?
Penicillins, cephalosporins, monobactams and vancomycin.
List classes of antibiotics?
1- beta- lactams.
2- macrolides.
3- quinolones.
4- aminoglycosides.
5- glycopeptides.
6- tetracyclines.
7- glycecyclines.
8- trimethoprim - sulfamethoxazole.
9- rifampin and rifabutine.
10- chloramphenicol.
11- metronidazole.
12- linconycoines.
13- streptogramins.
14- lipopeptides.
Give examples of beta-lactams?
1- penicillins.
2- cephalosporins.
3- monobactams.
4- carbapenems.
Give examples of macrolides?
1- erythromycin.
2- clarithromycin.
3- azithromycin.
Give examples of quinolones?
1- ciprofloxacin.
2- ofloxacin.
3- norfloxacin.
4- sparfloxacin d/ced.
5- levofloxacin.
6- trovafloxacin d/ced.
7- gatifloxacin d/ced.
8- moxifloxacin.
Give examples of aminoglycosides?
1- streptomycin.
2- gentamicin.
3- tobramicin.
4- amikacin.
Give an example of glycopeptides?
Vancomycin and teicoplanin.
Give examples of tetracyclines?
1- tetracycline.
2- doxycycline.
3- minocycline.
Give an example of glycecyclines?
Tigecycline.
Give an example of lincomycoines?
Clindamycin.
Give an example of streptogramins?
Quinupristin and dalfopristin.
Give an example of lipopeptides?
Daptomycin.
what is the MOA of beta-lactams?
inhibits cell wall synthesis (bactericidal).
beta lactams are bactericidal except against?
enterococcus sp.
beta lactams are _______ killers?
time-dependant killers.
beta lactams have ____ elimination half-time?
short.
how are beta lactams eliminated?
renally.
which beta lactams are not eliminated renally?
nafcillin.
oxacillin.
ceftriaxone.
cefoperazone.
beta lactams show cross _______?
cross- allergenicity.
which beta lactams doesn’t show cross allergenicity?
aztreonam.
what is the absorption of beta lactams?
variable depending on product.
what is the distribution method of beta lactams?
widely distributed into tissues and fluids.
which beta lactams only get into CSF in the presence of inflamed meninges?
pens
which Abx can penetrate the CSF?
parenteral 3rd and 4th generation cephs, meropenem and aztreonam.
what is the elimination method of beta lactams?
eliminated primarily by the kidney.
dosage adj of beta lactams required in the presence of ?
renal insufficiency.
which beta lactams are eliminated by the liver?
nafcillin,
oxacillin,
ceftriaxone.
all beta lactams have short elimination half-lives except?
a few cephalosporins (ceftriaxone).
list the neurological adverse effects of beta lactams?
irritability, confusion, seizures.
list the hematological adverse effects of beta lactams?
leukopenia, neutropenia, thrombocytopenia - prolonged therapy (>2).
list the gastrointestinal adverse effects of beta lactams?
increased LFTs , nausea, vomiting, diarrhea, pseudomembranous colitis (C.difficile diarrhea).
list the renal adverse effects of beta lactams and with which drugs?
cellular infiltration in renal tubules. especially with methicillin or nafcillin.
what is the most important and most common mechanism of resistance of beta lactams?
production of beta lactamase enzyme.
which beta lactam inhibits cross linking?
penicillin.
list the types of penicillins?
1- natural penicillins.
2- penicillinase - resistant penicillins.
3- aminopenicillins.
4- carboxypenicillins.
5- ureidopenicillins.
give examples of natural penicillins?
penicillin G, and penicillin VK.
give examples of penicillinase - resistant penicillins?
nafcillin, oxacillin, methicillin, cloxacillin.
give examples of aminopenicillins?
ampicillin, amoxicillin.
give examples of carboxypenicillins?
carbenicillin, ticarcillin.
give examples of ureidopenicillins?
piperacillin, azlocillin.
natural penicillins work the best agansit?
gram positive bacteria.
why were penicillinase-resistant penicillins developed?
overcome the penicillinase enzyme of S.aureus which inactivates natural penicillins.
penicillinase resistant penicillins work best against?
gram positive penicillinase s.aureus
why were aminopenicillins developed?
to increase activity against gram negative aerobes,
why were carboxypenicillins developed?
to further increase activity against resistant gram - negative aerobes.
carboxypenicillins work best against?
gram negative bacteria.
list beta lactamase inhibitor combos?
unasyn, augmentin, timentin, zosyn, tazocin.
why were beta lactamase inhibitor combos developed?
to gain or enhance activity against beta lactamase producing organisms.
cephalosporins are divided into generations based on what?
1- antimicrobial activity.
2- resistance to beta - lactamase.
list first gen cephalosporins?
cefazolin and cephalexin.
first generation cephalosporins have best activity against?
gram positive aerobes with limited activity against a few gram negative aerobes.
list the gram negative aerobes which first gen cephalosporins work against?
1- e.coli.
2- k.pneumoniae.
3- p.mirabilis.
list second generation cephalosporins?
cefuroxime.
cefuroxime-axetil.
cefoxitin.
cefotetan.
cefmetazole.
list activity spectrum of second gen cephalosporins?
slightly less active against gram positive aerobes, but more active against gram negative aerobes, little activity against anaerobes.
list the 2nd gen cephalosporins which have activity against anaerobes?
cefoxitin, cefotetan and cefmetazole.
list the spectrum of activity of cefoxitin, cefotetan and cefmetazole?
bacteroides fragilis and it’s group.
list third generation cephalosporins?
ceftriaxone, ceftazidime, cefotaxime, cefixime, cefdinir.
list the spectrum of activity of 3rd gen cephalosporins?
less active against gram positive aerobes but have greater activity against gram negative aerobes.
which cephalosporins have the best activity against gram positive aerobes including pen-resistant S.pneumoniae?
ceftriaxone and cefotaxime.