Macrolides

Question 1

Are macrolides lipid or water soluble?

Answer 1

Lipid soluble, so they concentrate intracellularly. Pass through the BBB.

Question 2

Do macrolides work in purulent debris?

Answer 2

Yes, they maintain their activity.

Question 3

Are macrolides bactericidal or bacteriostatic?

Answer 3

Mostly bacteriostatic, but may be bactericidal in some cases.

Question 4

How are macrolides eliminated?

Answer 4

Hepatic (Liver)

Question 5

How do macrolides work?

Answer 5

Inhibition of protein synthesis at the 50S ribosomal subunit.

Question 6

What are some mechanisms of resistance in macrolides?

Answer 6

Resistance can be chromosome or plasmid mediated.

Alteration of ribosomal subunits, change in drug permeability, and drug efflux mechanisms.

Question 7

Absorption of macrolides

Answer 7

40-90% oral absorption.

Question 8

What do macrolides work on?

Answer 8

Staph, strep, anaerobes + Mycoplasma.

Question 9

Tylosin

Answer 9

Staph, strep, anaerobes + Mycoplasma.

Question 10

Tilmicosin

Answer 10

Staph, strep, anaerobes, Mycoplasma + Pasteurella.

Question 11

What are some adverse rxns?

Answer 11

Macrolides may irritate tissues and hyperthermia due to anhydrosis in foals.
Erythromycin - GI disturbances common.
Tylosin - May cause colic in horses.
Tilmicosin - Injections toxic in swine, but can be used orally.

Question 12

Erythromycin

Answer 12

Drug of choice for Campylobacter enteritis.