Acos Powder for Suspension 30ml

Azithromycin is a macrolide antibiotic that remains stable in acidic conditions, allowing it to be taken orally without requiring protection from stomach acid. It is rapidly absorbed after oral administration, with better absorption when taken on an empty stomach. Peak blood concentrations are generally reached within 2.1 to 3.2 hours in adults.

One of its unique properties is its ability to accumulate inside phagocytic cells, which transport the drug directly to infected tissues. During the body's immune response, these cells release high concentrations of azithromycin at the site of infection. Tissue concentrations may become more than 50 times higher than plasma levels due to its high lipid solubility and ion-trapping characteristics.

Azithromycin has a prolonged elimination half-life, allowing once-daily dosing while maintaining therapeutic concentrations in infected tissues for several days. Following a single 500 mg oral dose, the drug demonstrates an average plasma clearance of approximately 630 mL/min and a terminal elimination half-life of about 68 hours. The prolonged half-life results from extensive tissue distribution followed by gradual release into circulation.

The drug is eliminated mainly through the bile in an unchanged form, while approximately 6% of the administered dose is excreted unchanged in the urine within one week

Antibacterial Spectrum

Azithromycin is active against many clinically important microorganisms, including:

Gram-positive bacteria

• Staphylococcus aureus
• Streptococcus agalactiae
• Streptococcus pneumoniae
• Streptococcus pyogenes
• Group C, F, and G streptococci
• Viridans streptococci

Gram-negative bacteria

• Haemophilus influenzae
• Haemophilus ducreyi
• Moraxella catarrhalis
• Neisseria gonorrhoeae
• Bordetella pertussis
• Legionella pneumophila

Other susceptible organisms

• Chlamydia trachomatis
• Chlamydia pneumoniae
• Mycoplasma pneumoniae

Anaerobic organisms

• Peptostreptococcus species
• Prevotella bivia

Azithromycin maintains activity against organisms that produce beta-lactamase enzymes.

Dosage & Administration

Oral Administration

Adults

• 500 mg once daily for 3 days, or
• 500 mg on Day 1, followed by 250 mg once daily on Days 2–5.

Sexually transmitted infections caused by Chlamydia trachomatis

• 1 g as a single oral dose, or
• 500 mg on Day 1, followed by 250 mg once daily for the next 2 days, as recommended by the physician.

Pediatric Dosage

For children older than 6 months:

• 10 mg/kg once daily for 3 days, or according to body weight:
  • 15–25 kg: 200 mg once daily for 3 days
  • 26–35 kg: 300 mg once daily for 3 days
  • 36–45 kg: 400 mg once daily for 3 days

Typhoid fever: 500 mg once daily for 7–10 days, as directed by the physician.

Intravenous Administration (IV Infusion)

Community-acquired pneumonia

• 500 mg IV once daily for at least 2 days, followed by 500 mg orally once daily to complete a 7–10 day treatment course.

Pelvic inflammatory disease

• 500 mg IV once daily for 1–2 days, followed by 250 mg orally once daily to complete 7 days of therapy.

When anaerobic bacteria are suspected, appropriate anaerobic antimicrobial therapy should be administered alongside azithromycin.

The safety and efficacy of injectable azithromycin have not been established in patients younger than 16 years.

Use azithromycin cautiously with the following medicines:

• Antacids: Take azithromycin at least 1 hour before or 2 hours after antacids containing aluminum or magnesium.
• Cyclosporine: Monitor cyclosporine blood levels and adjust dosage if necessary.
• Digoxin: May increase digoxin concentrations; monitoring is recommended.
• Warfarin: May be administered together, but regular monitoring of prothrombin time (PT/INR) is advised.
• Theophylline: Although significant interaction is uncommon, monitoring is recommended.
• Carbamazepine: No clinically significant interaction has been observed.
• Methylprednisolone: No significant pharmacokinetic interaction reported.
• Ergot derivatives: Concurrent use is contraindicated because of the potential risk of ergot toxicity.
• Terfenadine: No significant effect on QT interval has been demonstrated at recommended doses.