Azithromycin (Agycin) 500 mg 3's

Pronunciation

• a-ZITH-roe-MYE-sin

Trade Name

• Agycin

Classification

• Therapeutic: Antibiotic
• Pharmacologic: Macrolide

Pregnancy Category

• Category B

Indications

• Treatment of bacterial infections such as respiratory tract infections (including sinusitis and pneumonia), skin and soft tissue infections, ear infections, and sexually transmitted infections (such as chlamydia).
• Also used in the treatment of community-acquired pneumonia and pharyngitis/tonsillitis.

Mechanism of Action

• Azithromycin works by binding to the 50S ribosomal subunit of susceptible bacteria, inhibiting protein synthesis and thereby stopping bacterial growth (bacteriostatic effect).

Pharmacokinetics

• Absorption: Well absorbed orally; absorption can be affected by food.
• Distribution: Widely distributed throughout the body tissues; achieves higher concentrations in tissues compared to serum.
• Metabolism: Metabolized in the liver.
• Excretion: Primarily excreted in bile; a small amount is excreted in urine.
• Half-life: Approximately 68 hours.

Contraindications and Precautions

• Contraindications: Hypersensitivity to azithromycin, erythromycin, or any macrolide antibiotics.
• Precautions: Use with caution in patients with liver impairment, severe renal impairment, or those with a history of arrhythmias. Caution is also advised in patients with myasthenia gravis.

Adverse Reactions and Side Effects

• Common: Nausea, vomiting, diarrhea, abdominal pain.
• Serious: QT prolongation, hepatotoxicity, severe allergic reactions (anaphylaxis, Stevens-Johnson syndrome), Clostridium difficile-associated diarrhea.

Interactions

• Drug-Drug: May increase the effects of warfarin; can interact with drugs that prolong the QT interval (such as certain antiarrhythmics, antipsychotics, and antidepressants); may increase the levels of digoxin and cyclosporine.
• Food: Food can decrease the peak concentration; it is recommended to take azithromycin either 1 hour before or 2 hours after meals.

Route/Dosage

• Oral (Tablets): The typical dose for adults for most infections is 500 mg as a single dose on the first day, followed by 250 mg once daily for the next 4 days. For specific infections such as chlamydia, a single dose of 1 gram (1000 mg) may be used.
• Pediatric Dosage: Should be determined by a healthcare professional based on the type of infection and body weight.

Availability Formulations

• Agycin Tablets: Available in packs containing three 500 mg tablets.