click below
click below
Normal Size Small Size show me how
IOS 10 Exam 2
Macrolides & ketolides
Question | Answer |
---|---|
MOA of macrolides is | Reversible binding of the 50S subunit of domain V thus inhibiton of translation (same as clindamycin and chloramphemicol) |
MOA of ketolides | Reversible binding to Domain V and Domain II of 50 S subunit of ribosome thus blocking translation |
Macrolides are considered what type of killing | Bacterostatic for many but for S. pyrogenes (group A) and S. pneumoniae they are bacteriocidal. |
Resistance of macrolides | Permibility (gram-), enzymatic inactivation, efflux, single alterations in 23S subunit of 50S decreased binding, methylation of 23S subunit of 50S caused alteration o binding |
Resistance of ketolide | Scarce, alteration in telithromycin binding site via chromosomal or plasmid mutations |
Erythromycin ADME | inactivated byy gastric acids requires capsulation, distribution into all tissues (not CNS), metabolism via p450, elimination fecal |
Clarithromycin ADME | Good stability, extensive distribution,active metabolite |
Azrithromycin ADME | Acid stable, reduced with food. Hepatic metaoblism, Elimination may require weeks!!! |
Gram + aerobe activity of macrolides | Good,: staph, strep (poor-MRSA, enterococci) |
Gram- aerobic activity of macrolides | Moderate: neisseria gonorrhowae, M. catarrhalis, H. inf, Some activity against enterobacteriaw (shigellam campylobacter, vibrio) |
Anaerobic acitivty of macrolides | Little |
Atypical activity of macrolides | DRUGS OF CHOICE |
Other microbes macrolides cover | Borrelia burgdorferi, mycobacterium, H. pylori |
Macrolide side effects | GI (N/V, DIa), thrombophlebitis, ALL, hepatotoxic, ototoxic, superinfection, torsades de points, pseudomembraneous colitis |
Erythromycin DI | buspirone, carbamazepines, clomiramine respiradone, clozapine, cyclosporin, digoxin, felodpine, lovastatin, methylprednisolone, midazolam, phenytion, tacrolimus, theophylline,valproate, warfarin |
Claithromycin DI | carbamazepine, cyclosporin, digoxin, rifampin, rifabutin, ritnoravie, zidovudine |
Azithromycin DI | Cyclosporin |
Ketolides ADME | moderate abs, VD moderare 2.9L, T1/2 10 hours, metabolism is Cp450 inhibition (huge), with 80%various elimination methods |
Ketolide spectrum of activity: | Respiratory tract, S. pneumonia, pyrogenes, agalactiaw, H. infl, M. catarrhalis, C. pneumoniaw, L. pneumoniaw, M. pneumoniae, B. pertussis, MSSA |
Ketolide SE | GI most common, hepatotoxcity, ocular rate |
Ketolide DI | Simvastatin and lovastatin can cause increase in statin and decrease AB. Rifampin causes autoinduction of self and ketolides |