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Information |
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Drug Groups
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approved |
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Description
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Dirithromycin is a macrolide glycopeptide antibiotic. It is used to treat many different types of bacterial infections, such as bronchitis, pneumonia, tonsillitis, and even skin infections. |
| Indication |
For the treatment of the following mild-to-moderate infections caused by susceptible strains of microorganisms: acute bacterial exacerbations of chronic bronchitis, secondary bacterial infection of acute bronchitis, community-acquired pneumonia, pharyngitis/tonsilitis, and uncomplicated skin and skin structure infections. |
| Pharmacology |
Dirithromycin is a pro-drug which is converted non-enzymatically during intestinal absorption into the microbiologically active moiety erythromycylamine. Erythromycylamine exerts its activity by binding to the 50S ribosomal subunits of susceptible mircoorganisms resulting in inhibition of protein synthesis. Dirithromycin/erythromycylamine has been shown to be active against most strains of the following microorganisms both in vitro and in clinical infections: Staphylococcus aureus (methicillin-susceptible strains only), Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Legionella pneumophila, Moraxella catarrhalis, and Mycoplasma pneumoniae. |
| Toxicity |
The toxic symptoms following an overdose of a macrolide antibiotic may include nausea, vomiting, epigastric distress, and diarrhea. |
| Affected Organisms |
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Enteric bacteria and other eubacteria |
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| Biotransformation |
Dirithromycin is converted by nonenzymatic hydrolysis during absorption to the active compound, erythromycylamine. Sixty to 90% of a dose is hydrolyzed to erythromycylamine within 35 minutes after dosing, and conversion is nearly complete after 1.5 hours. Erythromycylamine undergoes little or no hepatic biotransformation. No other metabolites of dirithromycin have been detected in the serum. |
| Absorption |
Oral dirithromycin is rapidly absorbed, with an absolute bioavailability of approximately 10%. Dietary fat has little or no effect on the bioavailability of dirithromycin. |
| Half Life |
The mean plasma half-life of erythromycylamine was estimated to be about 8 h (2 to 36 h), with a mean urinary terminal elimination half-life of about 44 h (16 to 65 h) in patients with normal renal function. |
| Protein Binding |
15 to 30% for erythromycylamine, the active compound. |
| References |
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Brogden RN, Peters DH: Dirithromycin. A review of its antimicrobial activity, pharmacokinetic properties and therapeutic efficacy. Drugs. 1994 Oct;48(4):599-616.
[Pubmed]
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Wintermeyer SM, Abdel-Rahman SM, Nahata MC: Dirithromycin: a new macrolide. Ann Pharmacother. 1996 Oct;30(10):1141-9.
[Pubmed]
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Sides GD, Cerimele BJ, Black HR, Busch U, DeSante KA: Pharmacokinetics of dirithromycin. J Antimicrob Chemother. 1993 Mar;31 Suppl C:65-75.
[Pubmed]
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Counter FT, Ensminger PW, Preston DA, Wu CY, Greene JM, Felty-Duckworth AM, Paschal JW, Kirst HA: Synthesis and antimicrobial evaluation of dirithromycin (AS-E 136; LY237216), a new macrolide antibiotic derived from erythromycin. Antimicrob Agents Chemother. 1991 Jun;35(6):1116-26.
[Pubmed]
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