Macrolides azithromycin

Uncomplicated exacerbation Not requiring hospitalization Less than 3 exacerbations per year No comorbid illness I I V, greater than 50% predicted No recent antibiotic therapy Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis Oral Macrolide (azithromycin, clarithromycin) Second- or third-generation cephalosporin (cefuroxime, cefpodoxime, cefdinir, cefprozil) Doxycycline Ketolide (telithromycin) P-Lactam/P-Iactamase inhibitor (amoxicillin-clavulanate) Intravenous Not recommended... 

Macrolide Azithromycin, erithromycin, and telithromycin Streptococcal infections, lower and upper respiratory tract infections and pneumonia... 

In patients allergic to penicillin, macrolides are usually indicated in mild respiratory tract infections. Zithromax contains azithromycin, which is a macrolide that may be indicated for respiratory tract infections. As opposed to clarithromycin (another macrolide), azithromycin does not present any significant clinical interaction with phenytoin. Ciproxin contains ciprofloxacin. 

Azithromycin is an azalide antibiotic, a sub-class of the macrolides. Azithromycin differs chemically from erythromycin in that a methyl substituted nitrogen atom is incorporated into the lactone ring. 

Formation of this carbinolamine bond is revealed by the continuous electron density that connects the aldehyde group of the antibiotic to Hm A2103 in the unbiased electron density maps obtained for each of the 16-membered macrolides studied to date, each of which has an aldehyde group extending from C6. Not surprisingly, that continuous electron density feature is absent in the unbiased electron density map calculated for the structure of the 15-membered macrolide azithromycin which has no aldehyde group at C6. The electron density feature is consistent with formation of a carbinolamine bond and not with a SchifFbase, consistent with the expected chemical reactivity between exocyclic amines and aldehydes (Fig. 4.9) [21]. 

PROTEASE INHIBITORS MACROLIDES -AZITHROMYCIN Risk of T adverse effects of azithromycin with nelfinavir Possibly involves altered P-gp transport Watch for signs of azithromycin toxicity... 

THEOPHYLLINE ISONIAZID, MACROLIDES (azithromycin, clarithromycin, erythromycin, telithromycin), QUINOLONES 1. t theophylline levels 2. Possibly 1 erythromycin levels when given orally 1. Inhibition of CYP2D6-mediated metabolism of theophylline (macrolides and quinolones -isoniazid not known) 2.1 bioavailability uncertain mechanism 1. Monitor theophylline levels before, during and after co-administration 2. Consider alternative macrolide... 

Gastrointestinal symptoms were the most common adverse effects reported in a trial of azithromycin in disseminated Mycobacterium avium complex in 62 patients with AIDS (30). Erythromycin is a motilin receptor agonist (31-33). This mechanism may be at least partly responsible for the gastrointestinal adverse effects of macrolides. Azithromycin may act on gastrointestinal motility in a similar way to erythromycin, as it produces a significant increase in postprandial antral motility (34). 

Macrolides (azithromycin, clarithromycin. t Actin potential duration K+ channel blockade... 

Figure 4 Exemplar structures of various antibiotic classes that bind to either the 505 or the 305 subunit. Macrolides azithromycin (1), oxazolidinones linezolid (2), aminoglycosides Kanamycin A (3), Pleuromutilin (4), phenylpropanoids chloramphenicol (5), lincosamides clindamycin (6), Sparsomycin (7), Anisomycin (8), and tetracycline (9). See Scheme 9 for thiosptrepton (38). Not pictured streptogramins such as quinupristin/dalfopristin.

Third-generation macrolides, which include a 15-membered-ring macrolide, azithromycin, increase the acid stability of 14-membered-ring macrolides. Their pharmacokinetics is thus improved. These macrolides have high pK value but... 

Several groups of antimicrobial drugs are relatively safe in pregnancy, including penicillins and cephalosporins. While the macrolide azithromycin appears to be safe, the use of the esto-late form of erythromycin is associated with an increased incidence of cholestasis in the pregnant patient. Studies in animals have shown that clarithromycin is potentially embryotoxic. The answer is (A). 

Drugs in this class include erythromycin, tylosin, spiramycin, tylvalosin, carbomycin, oleandomycin, tilmi-cosin (all macrolides), azithromycin (an azalide), and... 

Macrolides Azithromycin, Clarithromycin, Dirithromycin, Erythromycin, Flurithromycin,Josamycin, Midecamycin, Rokitomycin, Roxithromycin, Spiramycin, Telithromycin, Troleandomydn... 

Erythromycin is a known inhibitor of the cytochrome P450 isoenzyme CYP3A4. However, this isoenzyme has only a minor role in the metabolism of warfarin , (p.358), specifically the less active R-isomer of warfarin. Consequently, only minor increases in the levels of warfarin have been seen in pharmacokinetic studies, which would generally not be expected to be clinically relevant. However, it is possible that even these small changes might be important in a very few patients, particularly those with a low prothrombin complex aetivity. Other macrolides (azithromycin, clarithromycin, dirithromycin, roxithromycin) have less effect on CYP3A4 than erythromycin, and consequently would be expected to have even less effect on the pharmacokinetics of warfarin or acenocoumarol, which is borne out in the few studies available. Nevertheless, cases of interactions have been reported for nearly all these macrolides. Moreover, one cohort study found that clarithromycin increased the risk of an interaction and erythromycin did not. It is possible that there is some other, as yet unidentified, mechanism involved. Alternatively, it is equally possible that the relatively few cases just represent idiosyncratic effects attributable to other factors, and not to any interaction (see also Coumarins -i- Antibacterials , p.365). 

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