Antibiotics: Others

Question 1

What fluoroquinolones should I know/ending?

Answer 1

ciprofloxacin, levofloxacin, gemifloxacin, moxifloxacin. Ending: “-floxacin”

Question 2

Fluoroquinolones: MoA

Answer 2

block DNA synthesis by inhibiting DNA gyrase (relaxes supercoils during replication) (also inhbitis topoisomerase IV at higher concentrations)
bactericidal

Question 3

Fluorquinolones: resistantce, cross-resistance?

Answer 3

lots of MoR: efflux pums, mutations in gyrase or topoisomerase, drug sequestration. cross-resistance is common.

Question 4

Fluoroquinolones: spectrum of action/ use

Answer 4

aerobic gram neg bacteria
some gram positive cocci
generally used to treat GI/GU infections by gram neg organisms.

Question 5

What toxicities are associated with fluoroquinolones? Special considerations?

Answer 5

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

Question 6

Sulfonamides: MoA

Answer 6

analogs of PABA
block folic acid synthesis: competitive inhibition of dihydropteroate synthetase
bacteriostatic

Question 7

What toxicities are associated with sulfonamides?

Answer 7

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

Question 8

Trimethoprim: MoA

Answer 8

folic acid inhibitor: inhibits dihydrofolate reductase. bacteriostatic

Question 9

What drug is trimethoprim combined with? Uses?

Answer 9

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.

Question 10

Toxicity of trimethoprim

Answer 10

megaloblastic anemia, leukopenia, granulocytopenia

Question 11

What are the four classes of beta-lactams?

Answer 11

penicillins, cephalosporins, monobactams, carbapenems

Question 12

What are the non-beta lactam cell wall synthesis inhibitors?

Answer 12

vancomycin and telavancin

Question 13

Beta lactams: MoA

Answer 13

inhibit transpeptidases: no crosslinking of peptides
activate autolysins: bacteria self-destruct
both of these are call penicillin binding proteins

Question 14

Vancomycin: MoA and uses and resistance mechanisms

Answer 14

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.

Question 15

What are the toxicities associated with beta lactams?

Answer 15

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)

Question 16

What is the spectrum of Penicillin G?

Answer 16

gram pos and some gram neg cocci, but most staphylococci and gonococci are now resistant.

Question 17

Pharmacokinetics of Penicillin G/V: ADE

Answer 17

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

Question 18

What are slow release penicillins?

Answer 18

benazathine penicillin and procaine penicillin. IM injection.

Question 19

What are the extended spectrum penicillins?

Answer 19

ampicillin and amoxicillin

others (ticarcillin, piperacillin, carbenicillin) active against pseudomonas

Question 20

What is tazobactam

Answer 20

like clavulanic acid: inhibits beta lactamase

Question 21

What is the quintessential beta lactamase resistant penicillin?

Answer 21

methicillin

Question 22

Efficacies of 1st and 2nd generation cephalosporins

Answer 22

first gen: PEcK (proteus mirabilis, e coli, kelbsiella pneumoniae)
second gen: HENPEcK (HiB, some enterobacter, neisseria)

Question 23

Cephalosporins are NOT active against which organisms?

Answer 23

LAME: listeria, atypicals like mycoplasma and chlamydia, MRSA, enterococci

Question 24

Vancomycin side effects

Answer 24

red man syndrome; NOT: nephrotoxic, ototoxic, throbophlebitis.