Azithromax 500 mg

Description

Indications
Azithromax is prescribed for infections caused by susceptible organisms. It is used for treating lower respiratory tract infections such as bronchitis and pneumonia, upper respiratory tract infections including sinusitis and pharyngitis/tonsillitis, otitis media, as well as skin and soft tissue infections. Additionally, Azithromax is effective in the treatment of sexually transmitted diseases such as non-gonococcal urethritis and cervicitis caused by Chlamydia trachomatis.

Pharmacology
Azithromycin is an acid-stable antibiotic that can be taken orally without requiring protection from gastric acids. It is well absorbed, with better absorption occurring on an empty stomach. Peak plasma concentration is reached within 2.1 to 3.2 hours after oral administration. Due to its high concentration in phagocytes, azithromycin is actively transported to infection sites, where large amounts are released during active phagocytosis. Tissue concentrations of azithromycin can be more than 50 times higher than plasma levels due to ion trapping and its high lipid solubility.

The extended half-life of azithromycin enables a single large dose to maintain bacteriostatic levels in infected tissues for several days. Following a single 500 mg dose, plasma concentrations decline in a polyphasic manner, with a mean apparent plasma clearance of 630 mL/min and a terminal elimination half-life of 68 hours. The primary route of excretion is biliary, where most of the drug is eliminated unchanged. Approximately 6% of the administered dose is excreted in urine over a week.

Mechanism of Action
Azithromycin works by binding to the 50S ribosomal subunit of susceptible microorganisms, thereby inhibiting microbial protein synthesis. However, it does not affect nucleic acid synthesis. The antibiotic is active against the following microorganisms:

• Aerobic and facultative gram-positive bacteria: Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Streptococcus pyogenes.
• Aerobic and facultative gram-negative bacteria: Haemophilus ducreyi, Haemophilus influenzae, Moraxella catarrhalis, Neisseria gonorrhoeae.
• Other microorganisms: Chlamydia pneumoniae, Chlamydia trachomatis, Mycoplasma pneumoniae.
• Anaerobic bacteria: Peptostreptococcus species, Prevotella bivia.

Dosage and Administration
Oral Administration:

• Adults: 500 mg once daily for 3 days or 500 mg on the first day, followed by 250 mg daily for the next 4 days.
• Sexually Transmitted Infections: A single 1 g dose, or alternatively, 500 mg on the first day followed by 250 mg daily for the next 2 days.
• Children:
  • 10 mg/kg once daily for 3 days (for children above 6 months).
  • 200 mg for 3 days (body weight 15-25 kg).
  • 300 mg for 3 days (body weight 26-35 kg).
  • 400 mg for 3 days (body weight 36-45 kg).
  • For typhoid fever: 500 mg daily for 7-10 days.

Intravenous (IV) Administration (for adults only):

• Community-Acquired Pneumonia: 500 mg IV once daily for at least 2 days, followed by 500 mg orally (two 250 mg tablets) daily to complete a 7-10 day course.
• Pelvic Inflammatory Disease: 500 mg IV once daily for 1-2 days, followed by 250 mg orally daily for 7 days. If anaerobic infection is suspected, an additional antimicrobial agent should be administered.

Reconstitution Procedure for Suspension

1. Shake the bottle well to loosen the powder.
2. Add boiled and cooled water up to the mark on the bottle label.
3. Shake until the powder is fully mixed with water.

Azithromycin should be taken at least 1 hour before or 2 hours after a meal.

Drug Interactions

• Antacids: Azithromycin should be taken at least 1 hour before or 2 hours after antacid administration.
• Carbamazepine & Methylprednisolone: No significant interactions have been observed.
• Cyclosporin & Digoxin: Monitor levels closely as macrolides may affect their metabolism.
• Ergot Derivatives: Co-administration is contraindicated due to the risk of ergotism.
• Theophylline & Warfarin: While no direct interactions have been found, monitoring is recommended.
• Terfenadine: No significant impact on cardiac repolarization was observed.

Contraindications

• Hypersensitivity to azithromycin or other macrolide antibiotics.
• Co-administration with ergot derivatives.
• Patients with hepatic impairment should avoid azithromycin use.

Side Effects
Azithromax is generally well tolerated, with most side effects being mild to moderate. Common adverse effects include:

• Gastrointestinal symptoms: Nausea, abdominal discomfort, vomiting, flatulence, diarrhea.
• Allergic reactions: Rash, photosensitivity.
• Liver function changes: Transient liver enzyme elevations, rare cases of cholestatic jaundice.
• Hematologic effects: Occasional mild reductions in neutrophil count.
• Hearing impairment: Reversible hearing loss in some patients receiving prolonged high doses.

Use During Pregnancy & Lactation
Azithromycin is classified as Pregnancy Category B, meaning no fetal harm has been demonstrated in animal studies, but adequate human studies are lacking. It should be used during pregnancy only if no safer alternatives are available. The presence of azithromycin in breast milk is unknown, so caution is advised when prescribing to lactating women.

Precautions & Warnings

• Serious allergic reactions, including angioedema and anaphylaxis, have been reported.
• Use caution in patients with severe renal impairment (creatinine clearance <40 mL/min).
• Since azithromycin is excreted via the liver, it should not be used in patients with hepatic disease.
• There is no evidence of impairment in driving ability while using azithromycin.

Overdose Effects
Overdose symptoms may include hearing loss, severe nausea, vomiting, and diarrhea. Treatment involves gastric lavage and supportive care.

Storage Conditions
Store in a dry place, away from light and heat. Keep out of reach of children.

Frequently Asked Questions (FAQs)

• What is Azithromax 500 mg Tablet used for?
  It is used to treat bacterial infections like pneumonia, throat infections, and sexually transmitted infections.
• Can Azithromax cause diarrhea?
  Yes, it may cause diarrhea as it affects gut bacteria. Seek medical advice if diarrhea persists or worsens.
• Is Azithromax safe?
  Yes, when used at prescribed doses as directed by a healthcare professional.
• What if I don’t feel better after taking Azithromax?
  Inform your doctor if symptoms persist or worsen after 3 days.

Quick Tips

• Complete the full course of Azithromax even if symptoms improve.
• Take on an empty stomach for better absorption.
• Avoid taking antacids 2 hours before or after.
• If an allergic reaction occurs, discontinue use and seek immediate medical attention.