Azithromycin

Azithromycin_structure

Azithromycin is a semisynthetic macrolide antibiotic commonly used to treat a wide variety of mild-to-moderate bacterial infections. It has been linked to rare instances of acute liver injury.

Mechanism of Action

Azithromycin (ay zith" roe mye' sin) is a semisynthetic macrolide antibiotic that is bacteriostatic against many gram-positive bacteria, including numerous strains of streptococci, staphylococci, clostridia, corynebacteria, listeria, haemophilus sp., moxicella, and Neisseria meningitidis. Azithromycin is more active than erythromycin against several gram-negative bacteria, as well as Mycoplasma pneumoniae, Helicobacter pylori, Toxoplasma gondii, cryptosporidia, and various atypical mycobacteria.

Macrolide antibiotics, such as azithromycin, erythromycin, and clarithromycin, inhibit bacterial protein synthesis by binding to the 50S ribosomal element. Resistance to these antibiotics can develop through several mechanisms.

Clinical Use

Azithromycin was approved for use in the United States in 1994, and it is currently the most commonly prescribed antibiotic in America. Typical indications for azithromycin include community-acquired pneumonia, acute exacerbations of chronic bronchitis, sinusitis, pelvic inflammatory disease, urethritis, and other infections caused by susceptible bacteria. Azithromycin is also used to treat disseminated Mycobacterium avium complex infections.

Dosage and Administration

Azithromycin is available as tablets of 250 and 500 mg, as well as solutions and powders for suspension, both generically and under the brand name Zithromax. It is typically administered in once-daily doses for 5 to 7 days. Chronic use of azithromycin is prescribed to treat atypical mycobacterial infections and as prophylaxis against common bacterial infections in highly susceptible individuals, such as those with cystic fibrosis, chronic granulomatous disease, or bronchiectasis. Parenteral azithromycin is usually given in doses of 500 mg intravenously daily for the first few days of therapy in moderate-to-severe infections.

Side Effects

Azithromycin is generally well-tolerated, but side effects can include nausea, abdominal pain, diarrhea, dyspepsia, headache, dizziness, angioedema, and rash.

Drug Interactions

Azithromycin may interact with certain medications, so it is essential to inform your healthcare provider about any other medications, supplements, or herbal products you are taking. Some known interactions include:

Anticoagulants, such as warfarin, may have an increased risk of bleeding when taken with azithromycin. Antiarrhythmic drugs, such as amiodarone and sotalol, can increase the risk of QT interval prolongation when taken with azithromycin. Digoxin levels may increase when taken with azithromycin, which may lead to digoxin toxicity. Carbamazepine, phenytoin, and other anticonvulsants may have reduced effectiveness when taken with azithromycin.

Precautions and Contraindications

Azithromycin should be used with caution in individuals with liver or kidney disease, as it is metabolized in the liver and excreted through the kidneys. It is also advised to use caution in patients with a history of QT interval prolongation or those at risk for developing cardiac arrhythmias. Azithromycin is contraindicated in individuals with a known hypersensitivity to macrolide antibiotics or any component of the medication.

Pregnant and breastfeeding women should consult with their healthcare providers before using azithromycin, as its safety during pregnancy and lactation has not been fully established.

Overdose and Treatment

In cases of azithromycin overdose, supportive care and monitoring should be provided. Gastric lavage may be considered if the ingestion is recent. There is no specific antidote for azithromycin overdose.

Storage and Disposal

Azithromycin should be stored at room temperature, away from light and moisture. It should be kept out of reach of children and pets. Unused or expired medication should be disposed of according to local guidelines or returned to a pharmacy for proper disposal.

Summary

Azithromycin is a semisynthetic macrolide antibiotic that is widely used to treat various mild-to-moderate bacterial infections. It is generally well-tolerated, but potential side effects include gastrointestinal symptoms, dizziness, and rash. Azithromycin may interact with certain medications, so it is crucial to inform your healthcare provider of any other drugs you are taking. Consult with your healthcare provider before using azithromycin if you have liver or kidney disease, a history of QT interval prolongation, or if you are pregnant or breastfeeding.

The following are macrolides

• Azithromycin
• Clarithromycin
• Erythromycin
• Fidaxomicin
• Telithromycin

• Dailymed label info on Azithromycin
• FDA Azithromycin

Azithromycin Resources
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