Clarithromycin - A Review

J E

Chief editor
DR T R RAMANUJAM M.D., C.MI.Biol (Lond)

INTRODUCTION

ANTIMICROBIAL ACTIVITY

CLINICAL PHARMACOKINETICS

CLINICAL EFFICACY

TOLERABILITY PROFILE

ADVERSE EFFECTS & DRUG INTERACTIONS

CHOOSING HOOSING MACROLIDES

CONCLUDING SUMMARY

BRIIGHTER SIDE OF CLARITHROMYCIN

DARKER SIDE OF CLARITHROMYCIN

CURRENT TRENDS IN MICROLIDE USE

CHOOSING MACROLIDES

Macrolides are important alternatives to betalactams in the treatment of number of infections. Major advantages of macrolides are that even though the spectrum covers the organisms amenable to benzyl penicillin, they are highly effectives against many intracellular pathogens by attaining high I.C concentration and high tissue fluid concentrations when compared with plasma concentrations..

Erythromycin, Azithromycin and Clarithromycin are equally effective against gram-positive infections.

Clarithromycin and azithromycin have better activity against H.influenzae, M.catarhalis, especially in the treatment of community acquired pneumonia and acute exacerbations of chronic bronchitis.

Clarithromycin is highly effective for treatment and prophylaxis of MAC (disseminated) infection in AIDS patients while Azithromycin is effective in prophylaxis alone.

Clarithromycin exhibits good activity against Gram Positive anaerobes, C.trachomatis, M.catarrhalis, L.pneumophiliae, H.influenzae and H.parainfluenzae, B.bdgedorferi, H.pylori, MAC, M.chelonae.

Clarithromycin is the drug of choice in H.pylori along with omeprazole in rapid eradication either in 3 or 4-drug regimen.

Azithromycin is the drug of choice in C.trachomatis, and gi en as single dose 1 G curative (Long plasma half life for azithromycin viz., 245-96 hrs). Unlike clarithromycin azithromycin does not affect CYP isoenzymes and there is no drug interaction.

Dirithromytcin is similar to Erythromycin in antibacterial activity Poor against H.influenzae but exhibit good activity against several strains of H.pylori.

Clarithromycin demonstrated activity against M.chelonae (disseminated cutaneous infection), disseminated MAC in AIIDS and in M.leprae.

Recent trials have demonstrated activity of clarithromycin against B>burgdorferi.

Azithromycin has increased activity against gram-negative organisms including H.influenzae, Enterobactericiae, Salmonellae, Shigellae, and E.coli, aerobic and anaerobic gram-negative organisms.

Roxithromycin is less effective than erythromycin well absorbed but food decreases absorption – usual dose is 150mg bd or 300mg/day.

Spiramycin (16membered macrolide from Str. aumbofauceus) is similar to erythromycin. A combination preparation with metronidazole is available for amebiasis. Spiramycin has no embryo toxicity, no teratogenecity, no mutagenecity and found to be active against Legionellirs, Toxoplasmosi, Chlamydiae and certain anaerobes (except B.fragilis and fusobacterium).

Spirmaycin exhibits very poor or no penetration into CNS.

Major indications of spiramycin include