Drugs under the macrolide group include?
Erythromycin, tylosin, tilmicosin, azithromyocin, clarithromycin
What is the mechanism of macrolides and are they cidal or static?
Inhibit protein synthesis by binding to the 50S ribosome subunit - bacteriostatic and time dependent
What are advanced generation macrolides?
Clarithromycin and azithromycin - longer half lives due to tissue uptake and then slow tissue release allowing for less frequent dosing
In what tissues do advanced generation macrolides accumulate in?
Do macrolides achieve high brain concentrations?
Why do macrolides concentrate in acidic environments?
Basic drug so will undergo ion trapping in acidic environments
How are macrolides metabolized and excreted?
Most are metabolized in the liver and excreted in the bile as metabolites and active drug, except tylosin and tilmicosin which are excreted unchanged in the bile and urine.
How do macroldes effect liver enzymes?
What antibiotic are macrolides similar to and sometimes substituted for? How do they differ?
Alternative to broad spectrum penicillins and first generation cephalosporins agains gram pos aerobes, gram neg aerobes and anaerobes. Not bacteriocidal
What are specific uses and spectrum of macrolides?
Gram pos and neg aerobes, Erythromycin w/rifampin tx of choice for R. equi in foals, Erthromycin is drug of choice for diarrhea and abortion due to C. jejuni in dog and foals; Tilmicosin used for bovine resp dz due to Mannheimia haemolytic and Pasteurella multicoda in cattle, mycoplasm infx, growth promoter in cattle and swine
Adverse effects of macrolides?
Irritation orally or paenterally, inhibition of GI flora in adult horse, hepatotoxicity, Tilmicosin is cardiotoxic when gien by IV injection in cattle or in some other species other than cattle
What causes the hepatotoxicity with some macrolides?