Antibiotics for Staph and Strep

Question 1

MOA of daptomycin

Answer 1

cyclic lipopeptide that rapidly disrupts bacterial cell membranes, loss of membrane potential and K+ efflux. Cidal!

Question 2

Daptomycin metabolism

Answer 2

90% protein bound and renally elminated

Question 3

Adverse effects of daptomycin

Answer 3

muscle pain/weakness

Question 4

DDR w/ daptomycin

Answer 4

caution when taking w/ statins

Question 5

MOA of linezolid

Answer 5

inhibits protein synthesis, binds 23S. Static and Cidal

Question 6

Linezolid metabolism

Answer 6

food delays absorption, non-enzymatically oxidized, no dose adjustment in renal failure. supplemental dose needed following hemodialysis

Question 7

Adverse effects of Linezolid

Answer 7

diarrhea, headache, N/V, myelosuppression associated w/ threrapy past 2 weeks, oral suspension contains Aspartame (warn pts w/ Phenylketonuria)

Question 8

DDR w/ Linezolid

Answer 8

1. non-selective MAO inhibitor so caution w/ co-admin of drugs metabolized by MAO.
2. HTN from decreased breakdown of tyramine absorbed from the diet

Question 9

adverse effects of clindamycin

Answer 9

1. pseudomembranous colitis
2. GI disturbances - diarrhea
3. HSR rashes

Question 10

adverse effect of bacitracin

Answer 10

severe nephrotoxicity w/ parenteral use

Question 11

MOA of Mupirocin

Answer 11

inhibits protein and RNA synthesis, binds reversibly to Staph isoleucly tRNA synthetase

Question 12

MOA of Bacitracin

Answer 12

inhibits bacterial cell wall synthesis by inhibiting dephosphorylation of the isoprenyl pyrophosphate carrier protein

Question 13

MOA of sulfamethoxazole

Answer 13

inhibits utilization of PABA in synthesis of folic acid, Static when used alone

Question 14

resistance to SMX

Answer 14

1. alteration in enzyme requiring PABA
2. increased inactivation of drug
3. alternative metabolic pathway
4. increased production of PABA

Question 15

Pharmacology of SMX

Answer 15

distributed everywhere, acetylated in liver, excreted renally

Question 16

adverse effects of SMX

Answer 16

1. crystalline aggregates in urinary tract
2. hematologic disorders (G6PD deficiency)
3. HSR
4. Drug potentiation w/ tolbuatmide, warfarin, MTX

Question 17

MOA of Trimethoprim

Answer 17

inhibits reduction of DHF to THF, highly selective for the bacterial enzyme

Question 18

Advantages of TMP-SMX

Answer 18

syngerigistic, and used 1:5 ratio

Question 19

adverse effects of TMP-SMX

Answer 19

hematologic effect - reversed w/ folic acid
HIV pts w/ PCP
Skin rxns are relatively common

Question 20

MOA of Vancomycin

Answer 20

Inhibits cell wall synthesis by binding to the D-alanyl-D-alanine terminus of cell wal

Question 21

adverse side effects of vancomycin

Answer 21

1. red man syndrome if infused too quickly
2. nephrotoxicity if used w/ aminoglycosides
3. otoxicity
4. neutropenia