Macrolides

Question 1

What is the MOA of Macrolides?

Answer 1

Bind reversibly to 50S ribosome may interfere with transpeptidation/translocation–> bacteriostatic P.S.I

Question 2

What are the pharmacokinetics?

Answer 2

A - oral. Unstable in acid. Decreased absorption with food.
D - wide (leukocytes and macrophages) not brain and CSF
M - potent CYP450 inhibitor
E - Via bile 5% in urine.

Question 3

Write 3 spectrum of activity?

Answer 3

Chlamydia, mycoplasma, legionella, gram + cocci

Question 4

What are the gaps in the spectrum?

Answer 4

Gram - bacilli

Question 5

What are some adverse effects?

Answer 5

Cholestasis
Auditory impairment - large IV doses
Prokinetic effect - diarrhoea
QT prolongation
Thrombophlebitis

Question 6

List the main clinical uses of macrolides

Answer 6

Upper and lower respiratory tract infections, STIs, H.pylori infections, prevent recurrent lung infections.

Question 7

What are notable adverse effects of ketolides?

Answer 7

Hepatoxicity, respiratory failure in myasthenia gravis.

Question 8

List 4 drug interactions of macrolides

Answer 8

Warfarin, Statins, Theophylline, antihistamines, ergot alkaloids

Question 9

List ways that macrolides can become resistant

Answer 9

Efflux pump, modification of ribosomal target, macrolide hydrolysis, mutations

Question 10

What can provide empiric cover against pneumonia?

Answer 10

Macrolide + beta lactam antibiotic