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12 Cards in this Set
- Front
- Back
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Macrolides
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-Erythromycin
prototype -Clarithromycin new derivative with improved spectrum and acid stability -Azithromycin new derivative with different pharmacokinetics as well as improved spectrum and acid stability |
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General Spectrum and Clinical Status
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-Good activity vs. common streptococci plus Bordetella, Chlamydiae , Mycoplasma, Legionella
-Treatment of common respiratory infections (Bordetella, Chlamydiae, Mycoplasma, Legionella) -Alternative to penicillin in mild-to-moderate infections (esp. common streptococci) |
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Chemistry and Mechanism
mech is similar to what other two drugs? |
-large lactone ring (14-15 membered) with aminosugars
-erythromycin base is acid labile use enteric coating and esters -new analogs with improved acid stability and spectrum Clarithromycin and Azithromycin -bacteriostatic inhibitor of protein synthesis -cindamycin and chloramphenicol |
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Therapeutic Uses
4 |
-Common URTI due to group A strep., Strep. pneumoniae, H. influenzae)
-Otitis media new analogs useful alone -Pneumonias due to Mycoplasma, Chlamydiae, and Legionella -Whooping cough (Bordetella pertussis) |
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Other Clinical Uses
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--Chronic bronchitis and sinusitis
-Helicobacter pylori in peptic ulcer disease -Mycobacterium avium complex infections in patients with AIDS Clarithromycin and Azithromycin |
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Spectrum
-Erythromycin -Clarithromycin -Azithromycin |
-Streptococci, some H. flu., syphilis, Mycoplasma, Rickettsia, Legionella, Bordetella
-improved to cover mycobacterium avium complex and H. pylori -similiar to clarithromycin plus increased potency vs. Chlamydiae, H. flu., some gram-neg. bacilli |
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Pharmacokinetics
-Absorption (oral) -Erythromycin -Clarithromycin -Azithromycin - |
-is acid labile (enteric coating or acid resistant esters used)
-taken with food -taken on empty stomach -good to most tissues (esp. lung, prostate) - inadequate to CSF -Azithromycin best; concentrated in phagocytic cells (macrophages) and fibroblasts |
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Excretion
Erythromycin Azithromycin Clarithromycin |
-hepatic metabolism (CYP3A)
some biliary secretion -feces as unchanged drug prolonged half-life (68 hrs) given for only 5 days -unchanged in urine (30%) and feces |
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Adverse Effects/ Drug Interactions
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-Erythromycin (Erythrocin)
GI irritation hepatotoxicity with estolate ester (adults) inhibits cytochrome P450 (CYP) metabolism -Clarithromycin (Biaxin) less GI effects inhibits CYP metabolism -Azithromycin (Zithromax) less GI effects no inhibition of CYP metabolism |
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Clinical Problems
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-Relatively safe drugs
mild GI disturbances -Bacteriostatic not used for serious infections susceptible to bactericidal drugs -Limited distribution not used for meningitis |
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New Macrolide Subclass
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ketolide /Telithromycin
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Telithromycin vs Macrolides
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-Improved activity vs. penicillin- and macrolide-resistant pathogens such as Streptococcus pneumoniae
-Good vs. chlamydiae, Mycoplasma, Bordetella, Legionella -Variable activity vs. Haemophilus influenzae |
