Antibiotics: Others Flashcards
What fluoroquinolones should I know/ending?
ciprofloxacin, levofloxacin, gemifloxacin, moxifloxacin. Ending: “-floxacin”
Fluoroquinolones: MoA
block DNA synthesis by inhibiting DNA gyrase (relaxes supercoils during replication) (also inhbitis topoisomerase IV at higher concentrations)
bactericidal
Fluorquinolones: resistantce, cross-resistance?
lots of MoR: efflux pums, mutations in gyrase or topoisomerase, drug sequestration. cross-resistance is common.
Fluoroquinolones: spectrum of action/ use
aerobic gram neg bacteria
some gram positive cocci
generally used to treat GI/GU infections by gram neg organisms.
What toxicities are associated with fluoroquinolones? Special considerations?
Must not take with an aticacid.
GI common
potential for long QT syndrome, esp. with gemifloxacin/moxifloxacin
can cause tendon rupture
contraindicated in pregnancy b/c of possible damage to cartilage
Sulfonamides: MoA
analogs of PABA
block folic acid synthesis: competitive inhibition of dihydropteroate synthetase
bacteriostatic
What toxicities are associated with sulfonamides?
hypersensitivities, including fatal Stevens-Johnson syndrome
hemolysis in Glu-6-P dehydrogenase deficient patients
kernicterus in neonates (bilirubin induced brain damage).
can reduce warfarin binding to albumin
Trimethoprim: MoA
folic acid inhibitor: inhibits dihydrofolate reductase. bacteriostatic
What drug is trimethoprim combined with? Uses?
sulfamethoxazole:
TMP-SMX or TMP-SMZ
used to treat UTIs, shigella, salmonella, pneumocystis jirovecii prophylaxis and treatment, toxoplasmosis prophylaxis. start prophylactically at CD4 <200 for pneumocystis and less than 100 for toxo.
Toxicity of trimethoprim
megaloblastic anemia, leukopenia, granulocytopenia
What are the four classes of beta-lactams?
penicillins, cephalosporins, monobactams, carbapenems
What are the non-beta lactam cell wall synthesis inhibitors?
vancomycin and telavancin
Beta lactams: MoA
inhibit transpeptidases: no crosslinking of peptides
activate autolysins: bacteria self-destruct
both of these are call penicillin binding proteins
Vancomycin: MoA and uses and resistance mechanisms
binds D-ala-D-ala of the peptides and is so sterically bulky that it inhibits transglycosylases: no sugar polymerization. may only be used for gram positive organisms.
resistance when bactria go from D-ala D-ala to D-ala-D-lac.
What are the toxicities associated with beta lactams?
mostly hypersensitivies. all beta lactams are cross-sensitizing and cross-reacting
ALSO MUST KNOW: cephalosporins like cefotetan can inhibit vitamin K dependent blood clotting enzymes and have major beeding side effects and cause a disulfiram-like rxn to alcohol (SUPER hangover)
What is the spectrum of Penicillin G?
gram pos and some gram neg cocci, but most staphylococci and gonococci are now resistant.
Pharmacokinetics of Penicillin G/V: ADE
water soluble
excreted by kidneys
distributed everywhere but prostate and CNS, though CNS distribution greater when CNS is inflammed
Penicillin G must be administered IV; V is ok to take orally
What are slow release penicillins?
benazathine penicillin and procaine penicillin. IM injection.
What are the extended spectrum penicillins?
ampicillin and amoxicillin
others (ticarcillin, piperacillin, carbenicillin) active against pseudomonas
What is tazobactam
like clavulanic acid: inhibits beta lactamase
What is the quintessential beta lactamase resistant penicillin?
methicillin
Efficacies of 1st and 2nd generation cephalosporins
first gen: PEcK (proteus mirabilis, e coli, kelbsiella pneumoniae)
second gen: HENPEcK (HiB, some enterobacter, neisseria)
Cephalosporins are NOT active against which organisms?
LAME: listeria, atypicals like mycoplasma and chlamydia, MRSA, enterococci
Vancomycin side effects
red man syndrome; NOT: nephrotoxic, ototoxic, throbophlebitis.
