Macrolides

Question 1

Erythromycin
(Protein Synthesis Inhibition - bacteriostatic)
(Broad spectrum)
(Strept, Staph (MRSA, MSSA), Mycoplasma pneumoniae, Chlamydia/Gonorrhea)

Answer 1

Binds 50S, inhibits translocation of peptidyl tRNA
Admin: Oral
Penetrates everywhere, incl placenta (except CSF)
Hepatic excretion (bile)

Question 2

Azithromycin
(Protein Synthesis Inhibition - bacteriostatic)
(Broad spectrum)
(Strept, Staph (MRSA, MSSA), Mycoplasma pneumoniae, Chlamydia/Gonorrhea)

Answer 2

Binds 50S, inhibits translocation of peptidyl tRNA
Admin: Oral (w/out food)
Penetrates everywhere, incl placenta (except CSF)
Hepatic excretion

Question 3

Clarithromycin
(Protein Synthesis Inhibition - bacteriostatic)
(Broad spectrum)
(Strept, Staph (MRSA, MSSA), Mycoplasma pneumoniae, Chlamydia/Gonorrhea)

Answer 3

Binds 50S, inhibits translocation of peptidyl tRNA
Admin: Oral (w/ food)
Penetrates everywhere, incl placenta (except CSF)
Renal excretion

Question 4

Resistance

Answer 4

Methylation of 50S ribosome via MDR gene (S pneumoniae and H flu), multidrug efflux via MDR

Question 5

Side Effects and Drug Interactions

Answer 5

SE: Erythro is the WORST - all exhibit nausea, vomiting, diarrhea, anorexia, hepatitis, QT elongation –> ventricular arrhythmias
DI: Erythro & Clarithro- can inhibit C450 (allow other drugs to accumulate)
Azithro - NONE