1 / 9

MACROLIDES

Macrolides ( cont. ). PharmacokineticsErythromycin baseAbsorption incomplete but adequate from intestineInactivated by gastric HCL, hence given as :Enteric coated tablets or ester (stearate, ethyl succinate )Food delays absorptionNot metabolized and actively secreted in bile ( major route of e

rehan
Download Presentation

MACROLIDES

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. MACROLIDES Erythromycin Clarithromycin Azithromycin Mechanism of action Inhibit protein synthesis by binding to the 50 s subunit Antibacterial activity Bactericidal or bacteriostatic, depending on the concentration and type of bacteria

    2. Macrolides ( cont. ) Pharmacokinetics Erythromycin base Absorption incomplete but adequate from intestine Inactivated by gastric HCL, hence given as : Enteric coated tablets or ester (stearate, ethyl succinate ) Food delays absorption Not metabolized and actively secreted in bile ( major route of excretion ) Only 2-5 % is excreted in active form in urine Widely distributed into most tissues, except the brain and CSF Cross the placental barrier Protein binding 70- 80 % Half life approx. 1.6 hr

    3. Clarithromycin Pharmacokinetics Acid stable Food delays absorption but doesnt alter its extent Metabolized by the liver to 14- hydroxy clarithro. ( active ) Widely distributed, except brain and CSF Protein binding 40 70 % Excreted in Urine unchanged 20 40 % 14- H. clarithromycin 10 15 % Biliary Half- life clarithromycin 3 7 hr 14 H. clarithromycin 5- 9 hr Advantage over erythromycin Lower frequency of GI intolerance Less frequent dosing ( twice daily )

    4. MACROLIDES ( cont. ) Azithromycin Pharmacokinetics Rapidly absorbed from GIT Food delays absorption Widely distributed ( extensive tissue distribution ), except CSF Protein binding 51% Undergo some hepatic metabolism ( inactive ) Biliary route is the major route of elimination Only 6% is excreted unchanged in the urine Half- life approx. 3 days Advantage over erythromycin & clarithromycin Once daily dosing No inhibition of cytochrome P- 450

    5. Macrolides ( cont. ) Antibacterial spectrum Erythromycin Mainly effective on G+ bacteria A. Gram- positive bacteria Staph. Aureus S. pneumoniae URTIs ( eg. Otitis media, pharyngitis ) LRTIs ( eg. Pneumoniae ) S. pyogens C. diphtheria B. Gram- negative bacteria T. pallidum C. Intracellular organisms L. pneumophila M. pneumoniae C. trachomatis

    6. Indications for erythromycin 1. Alternative to penicillin in allergic pts ( Staph.Aureus, S. pyogens, S.pneumoniae or T.pallidum ) 2. Diphtheria & whooping cough drug of choice 3. Legionnaires disease- drug of choice 4. Pneumoniae ( M. pneumoniae ) children 5. Chlamydia trachomatis

    7. Clarithromycin Antibacterial spectrum A. Gram- positive bacteria Staph. Aureus S. Pneumoniae S. Pyogens B. Gram- negative bacteria H. influenzae H. Pylori M. catarrhalis C. Intracellular organisms M. pneumoniae L. Pneumophila Indications Pharyngitis / tonsilitis Otitis, sinusitis Adjunct in treatment of duodenal ulcer ( H. pylori )

    8. Azithromycin Mainly effective on G- bacteria but less active against G+(s.pneumoniae & s.pyogenes) than erythromycin Antibacterial spectrum A. Gram- positive bacteria Staph. Aureus S. Pneumoniae S. Pyogens B. Gram- negative bacteria (> erythromycin) M. catarrhalis H. influenzae C. Intracellular organisms (> erythromycin) L. Pneumophila M. pneumoniae Chlamydia species Indications Pharyngitis/ tonsilitis ( s. pyogens ), otitis, sinusitis ( Staph. Aureus & H. influenzae ) Uncomplicated genital chlamydial infections

    9. Side effects of macrolides Nausea, vomiting, abdominal pain & diarrhea( AAC) Allergic reactions- urticaria, mild skin rashes Sore mouth

More Related