Macrolide antibiotics newer

Newer and more generally usefnl macrolide antibiotics include azithromycin (Zithromax) and clarithromycin (Biaxin). These too are wide-spectrum antibiotics and both are semisynthetic derivatives of erythromycin. Like the tetracyclines, the macrolide antibiotics act as protein synthesis inhibitors and also do so by binding specifically to the bacterial ribosome, thongh at a site distinct from that of the tetracyclines. 

Cunha, B. A. (1996). Newer macrolide antibiotics Advantages and uses. Adv. Therapy 13, 29-37. Kirst, H. A., and Sides, G. D. (1989). New directions for macrolide antibiotics Pharmacokinetics and clinical efficacy. Antimicrob. Agents Chemother. 33, 1419-1422. 

Many Hj antihistamines are metabolized by CYPs. Thus, inhibitors of CYP activity such as macrolide antibiotics (e.g., erythromycin) or imidazole antifungals (e.g.,ketoconazole) can increase Hj antihistamine levels, leading to toxicity. Some newer antihistamines, such as cetirizine, fexofenadine, levocabastine, and acrivastine, are not subject to these drug interactions. 

Erythromycin, from the actinomycete Saccharo-polyspora (formerly Streptomyces) erythraea, is the first member of this family of antibiotics to be marketed and successfully used clinically to treat infections in humans. It has an antimicrobial spectrum at least as wide as the penicillins, and interestingly, from our perspective, it is often used as a replacement for patients allergic to that group of drags. Besides erythromycin, other members of the macrolide family of antibiotics that are clinically useful include azithromycin, clarithromycin, dirithromycin, roxithromycin, telithromycin (these six are approved by the FDA), oleandomycin, and spiramycin. Clarithromycin, dirithromycin, and roxithromycin and the azalide azithromycin are more recent members of the group and can be regarded as newer generation macrolide antibiotics. 

COPD exacerbations. Therefore, in exacerbation treatment with antibiotics is justified when the patient has at least two of three features of increased dyspnea, increased sputum volume, and sputum pu-rulence. Antibiotic choice will depend on local experience derived from local bacteriological sensitivity data. Older, less costly compounds such as tetracycline, doxycycline, amoxicillin, erythromycin, cefaclor etc. are often as effective as newer, more expensive ones. If resistant organisms are suspected or when the severity of the patients clinical condition puts them at high-risk of treatment failure, a second or third generation cephalosporin, fluoroquinolone, newer macrolide or broad-spectrum penicillin may be preferred. In cases of recurrent infection prolonged courses of antibiotics continuous or intermittent, may be useful. 

The gastrointestinal adverse effects are the most common untoward effects of the macrolides (Table 2). Nausea and vomiting associated with abdominal pain and occasionally diarrhea can be minor and transitory or, in a small percentage of patients, become severe enough to result in premature withdrawal. The rate of these adverse effects varies among the different antibiotics. In general, newer macrolides, such as azithromycin, clarithromycin, or roxithromycin, are better tolerated and cause fewer adverse effects than erythromycin. 

Erythromycin can cause two different types of liver damage (36,37), benign increases in serum transaminases, which may or may not recur on rechallenge, and cholestatic hepatitis. Reports of intrahepatic cholestasis with azithromycin (38), clarithromycin (39,40), and josamycin (41) suggest that the newer macrolides are not free of this adverse effect, although the relative risks compared with erythromycin are unclear. Similar involvement of the liver has been seen with the ester of triacetyloleandomycin, but not with the unesterified antibiotic. 

Maaolides are appropriate antibiotics for the management of respiratory tract infections because they are active against Streptococcus pneumoniae. Streptococcus pyogenes (group A streptococci), and atypical organisms such as Legionella pneumophila. Mycoplasma pneumoniae, and Chlamydia pneumoniae. The newer generation macrolides such as clar-... 

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