The new macrolide antibiotics: azithromycin, clarithromycin, dirithromycin, and roxithromycin.
OBJECTIVE
To review the chemistry, antimicrobial spectrum, pharmacokinetics, clinical trials, adverse effects, and drug interactions of four new macrolide antibiotics: azithromycin, clarithromycin, dirithromycin, and roxithromycin.


METHODS
Information was obtained from comparative clinical trials, abstracts, conference proceedings, and review articles. Indexing terms included azithromycin, clarithromycin, dirithromycin, erythromycin, roxithromycin, and macrolide antibiotics.


METHODS
Emphasis was placed on comparative clinical trials involving the new macrolide antibiotics.


METHODS
Data from human studies published in the English language were evaluated. Trials were assessed by sample size, macrolide dosage regimen, and therapeutic response.


RESULTS
The erythromycins have gained widespread use in treating a variety of infections. Although they are effective, limitations include the need to administer four times a day and the intolerable adverse gastrointestinal effects. Four of the more extensively studied agents, azithromycin, clarithromycin, dirithromycin, and roxithromycin, are currently being studied in patients. Based on the studies to date, the newer macrolides may offer several advantages over erythromycin, including: (1) greater antimicrobial activity against certain organisms; (2) longer elimination half-life, thus allowing less frequent administration; and (3) lower incidence of adverse gastrointestinal effects.


CONCLUSIONS
The new macrolide antibiotics appear to offer an improvement over erythromycin. Definitive conclusions about the role of these drugs should await completion of ongoing clinical studies.
Bahal
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Ohio State University (OSU), College of Pharmacy 43210.
Nahata
M C
MC
D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D017963:Azithromycin; D017291:Clarithromycin; D002986:Clinical Trials as Topic; D004347:Drug Interactions; D004917:Erythromycin / Q000031:analogs & derivatives / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D018942:Macrolides; D015575:Roxithromycin / Q000737:chemistry / Q000493:pharmacokinetics / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D018942:Macrolides; C053853:dirithromycin; D015575:Roxithromycin; D004917:Erythromycin; D017963:Azithromycin; D017291:Clarithromycin