Azithromycin which generation

Pharmacodynamic models and susceptibility breakpoints derived from studies with other classes of drugs, such as the beta-lactams and aminoglycosides, do not adequately explain the clinical utility of antibacterial agents that achieve high intracellular concentrations. In the case of azithromycin, attention should focus on tissue pharmacokinetic and pharmacodynamic concepts. Abstract The azalide antibiotic azithromycin and the newer macrolides, such as clarithromycin, dirithromycin and roxithromycin, can be regarded as 'advanced-generation' macrolides compared with erythromycin, the first macrolide used clinically as an antibiotic.

Publication types Review. It inhibits bacterial protein synthesis by preventing the transit of aminoacyl-tRNA and the growing protein through the ribosome. Compared to erythromycin, azithromycin is less prone to disassociation from the gram-negative ribosome, conferring its greater efficacy against gram-negative pathogens.

However, especially at higher doses, azithromycin has been shown to have a bactericidal effect against certain bacteria such as streptococci and H. Pharmacokinetically, azithromycin rapidly moves from the bloodstream into tissues and, once there, readily crosses cellular membranes, allowing efficacy against intracellular pathogens.

By inducing the expression of RIG-I-like helicases, azithromycin enhanced rhinovirus-induced expression of interferons in cultured cells of COPD patients but not in cultured cells of healthy patients in vitro. Azithromycin is available for both oral and parenteral intravenous administration. The extended-release formulation of azithromycin has been discontinued. The usual dose is mg or mg given once daily for 3 to 5 days, and in severe infections, a higher dose is used.

Azithromycin demonstrates excellent tissue penetration and intracellular accumulation. Metabolism is hepatic, and excretion is mainly biliary. Azithromycin may be administered to patients with renal disease or failure without regard for creatinine clearance. No dose adjustment is usually necessary. Azithromycin is generally regarded as a safe antimicrobial agent, and only a few patients discontinue azithromycin due to adverse effects. Azithromycin is contraindicated in patients with a history of severe hypersensitivity e.

In addition, clinicians should be cautious regarding the concomitant use of azithromycin and other medications that prolong the QTc interval e. Azithromycin is contraindicated for patients taking the first-generation antipsychotic pimozide. Macrolide antimicrobials inhibit CYP3A4, the same cytochrome that metabolizes pimozide; concomitant use of azithromycin with pimozide can cause dangerous plasma concentrations of pimozide, leading to QTc prolongation and, potentially, lethal arrhythmias.

While azithromycin is a poor inhibitor of CYP3A4 relative to other macrolides, avoidance of this interaction is still advisable. Drugs that are substrates of P-glycoprotein, particularly those that are also substrates of CYP3A4, may represent a relative contraindication to azithromycin.

Examples include colchicine and small-molecule calcitonin gene-related peptide CGRP antagonists. Most courses of treatment with azithromycin are short, and adverse effects requiring therapy adjustment or discontinuation of azithromycin are rare. For patients receiving long-term azithromycin prophylaxis e. In these patients, reduction of the dose or twice-daily dosing may be a consideration.

Azithromycin, like other macrolides, is associated with QTc prolongation. Particularly in patients with a known history of QTc interval perturbation, cardiac arrhythmia, or concomitant use of other medications associated with QTc prolongation, azithromycin can result in dangerous or potentially lethal arrhythmias such as torsades de pointes.

In animal studies, although azithromycin was associated with similar QTc prolongation compared to other macrolides, azithromycin seemed to have a smaller proarrhythmic effect. With prompt discontinuation of azithromycin, liver injury is almost always reversible with minimal residual impairment. Often, azithromycin-induced hepatotoxicity has associated immunoallergic features such as rash, fever, and eosinophilia. Gastrointestinal toxicity is common but typically mild, and most patients complete the prescribed course of azithromycin.

Although azithromycin is a generally well-tolerated, efficacious antimicrobial agent, with many clinical indications, it is commonly inappropriately prescribed, particularly in the primary care setting. Several large retrospective cohort studies that demonstrated high levels of inappropriate antimicrobial prescribing overall singled out azithromycin as the most frequently misused drug.

Azithromycin is frequently prescribed when there is no clinical indication for antimicrobials and in many instances in which azithromycin is not first-line therapy e. Azithromycin is a frequent antimicrobial therapy prescribed in situations in which a narrow-spectrum beta-lactam e. One possible association with high rates of azithromycin prescription is patient-reported penicillin allergy. Researchers found Which of the following species of bacteria are known to produce mecA?

Derek W. Second Generation. Fourth Generation. Antibiotic Grouping By Mechanism. Penicillins bactericidal: blocks cross linking via competitive inhibition of the transpeptidase enzyme.

Cephalosporins bactericidal: inhibits bacterial cell wall synthesis via competitive inhibition of the transpeptidase enzyme. Folic acid Synthesis Inhibitors. Please rate topic. Upgrade to PEAK.

QID: Question Importance. L 1 Question Complexity. L 2 Question Complexity. L 4 Question Complexity. Sort by. All Videos 0 Podcasts 2. Listen Now min. Rachel Hoppner OB. Please login to add comment. Cancel Save. First generation.

Amikacin Gentamicin Kanamycin Neomycin Tobramycin. Ertapenem Imienem Meropenem. Azithromycin Clarithromycin Dirithromycin Erythromycin Clindamycin. Penicillinase Resistant. Methicillin Nafcillin Oxacillin other. Cefacor Cefotetan Cefotan other.

Third Generation. Cefpirome Cefepime. Cell Wall Synthesis. Protein Synthesis Inhibitors. Fluoroquinolones Metronidazole. RNA synthesis Inhibitors. Mycolic Acid synthesis inhibitors. Folic Acid synthesis inhibitors.

Inhibits Cell Wall Synthesis. Hypersensitivity reaction Hemolytic anemia. Methicillin Nafcillin Oxacillin Cloxacillin Dicloxacillin.