| Table 10: | ||||
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Macrolides
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Azithromycin
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Clarithromycin
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Dirithromycin
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Erythromycin
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| Brand names | Zithromax | Biaxin | Dynabac | Various |
| Absorption | 37% | 50% | 10% | 18-45% |
| Half-life | 68 h | 5-7 h | 8 h | 1.5-2 h |
| Metabolism | Significant | Significant | Some | Significant |
| Excretion | 50% unchanged in bile, 12% in urine | Primary renal | Primary via bile | Primary in feces and bile |
| Mechanism of drug interactions | Mild inhibition of CYP 3A3/4 | **Multiple drug interactions; significant inhibition of CYP 3A3/4 and 1A2 | **Interactions may be similar to those of erythromycin | **Multiple drug interactions; significant inhibition of CYP 3A3/4 and 1A2 |
| Approved indications* | CAP, pharyngitis/ tonsillitis, AECB, skin, genital ulcers, urethritis, and cervicitis, OM, MAI, PID | CAP, pharyngitis/ tonsillitis, AECB, skin, MAI, OM, sinusitis, Helicobacter pylori (in combination) | CAP, pharyngitis/ tonsillitis, AECB, skin | Indicated by activity against specific organisms for treatment of a wide variety of infections |
| Ususal
dose** (adults) |
250-500 mg daily. Single doses of 1 g for some STDs. Weekly doses of 1200 mg for MAI prophylaxis. | 250-500 mg q12h or 1000 mg daily (extended release only). | 500 mg daily for 5-14 days | 250-1000 mg q6h |
| Usual
dose** (pediatrics) |
15 mg/kg/d divided every 12 h |
--
|
PO: 30-50 mg/kg/d
divided every 6-8 h |
|
| Other considerations | Dose adjustment necessary in renal insufficiency | |||
| Dosage forms | Injection:
500 mg Suspension: 100 mg/ 5 ml, 1 g single dose Tablet: 250 mg, 600 mg |
Tablet:
250 mg, 500 mg, 500 mg extended release Suspension: 125 mg/ 5 ml, 187.5 mg/ 5 ml, 250 mg/ ml |
Tablet: 250 mg | More than 25 different dosage forms available in 6 different salt forms. IV, oral, solids, and liquids and chewables available. |
| *CAP=community
acquired pneumonia, AECB=acute exacerbation of chronic bronchitis, MAI=Mycobacterium
avium infections, OM=otitis media, UTI=urinary tract infection, Skin=skin
and soft tissue infection, PID=pelvic inflammatory disease, STD=sexually
transmitted disease. **Check product information for the specific dosing that corresponds with specific indication. |
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Copyright
2002 The Cleveland Clinic Foundation
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