Zimax 500 mg

Description

Indications
Zimax is prescribed for infections caused by susceptible microorganisms, including 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. It is also used in the treatment of sexually transmitted infections, specifically non-gonococcal urethritis and cervicitis caused by Chlamydia trachomatis.

Pharmacology
Azithromycin is an acid-stable antibiotic, allowing it to be administered orally without requiring protection from stomach acids. It is well-absorbed, with optimal absorption occurring on an empty stomach. Peak plasma concentrations in adults are typically reached within 2.1 to 3.2 hours after oral administration. Azithromycin is concentrated in phagocytes and transported to the infection site, where it is actively released during phagocytosis. Tissue concentrations of azithromycin can exceed plasma levels by over 50 times due to its lipid solubility and ion trapping properties.

Azithromycin has a prolonged half-life, enabling effective bacterial suppression with a single large dose. Following a 500 mg dose, the plasma concentration declines in a polyphasic manner, with an average clearance of 630 mL/min and a terminal elimination half-life of 68 hours. The drug is primarily excreted via bile, with a minor portion (approximately 6%) excreted unchanged in urine over one week.

Mechanism of Action
Azithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit of susceptible microorganisms, preventing the translation process. It does not interfere with nucleic acid synthesis.

Spectrum of Activity:
Azithromycin is effective against various pathogens, including:

• 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:

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

Intravenous (IV) Infusion:

• Community-acquired pneumonia: 500 mg once daily by IV for at least two days, followed by oral azithromycin (500 mg daily as two 250 mg tablets) for 7-10 days.
• Pelvic inflammatory disease: 500 mg once daily by IV for one or two days, followed by oral azithromycin (250 mg daily) to complete a 7-day course.

Reconstitution of Suspension:

1. Shake the bottle well to loosen the powder.
2. Add boiled and cooled water up to the marked level on the bottle.
3. Shake until the powder is completely dissolved.

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

Drug Interactions

• Antacids: Take azithromycin at least 1 hour before or 2 hours after antacids.
• Carbamazepine: No significant interaction observed.
• Cyclosporine: Monitor cyclosporine levels if co-administered.
• Digoxin: May lead to elevated digoxin levels; monitoring is advised.
• Ergot derivatives: Co-administration is contraindicated due to the risk of ergotism.
• Methylprednisolone & Theophylline: No significant interaction observed.
• Warfarin: Regular monitoring of prothrombin time is recommended.
• Terfenadine: No significant effect on cardiac repolarization observed.

Contraindications

• Hypersensitivity to azithromycin or other macrolide antibiotics.
• Co-administration with ergot derivatives.
• Patients with hepatic disease.

Side Effects
Zimax is generally well tolerated. Common side effects include gastrointestinal discomfort, nausea, vomiting, flatulence, diarrhea, and abdominal pain. Rare allergic reactions such as rash or photosensitivity may occur. Infrequent cases of cholestatic jaundice and transient reductions in neutrophil counts have been reported. Hearing impairment has been observed in some patients receiving prolonged high doses.

Use During Pregnancy & Lactation

• Pregnancy: Classified as Category B. No evidence of fetal harm has been found in animal studies, but human data are insufficient.
• Lactation: It is unknown whether azithromycin is excreted in breast milk; caution is advised.

Precautions & Warnings

• Rare but serious allergic reactions, including angioedema and anaphylaxis, have been reported.
• Patients with renal impairment (creatinine clearance <40 mL/min) should use with caution.
• Should not be used in patients with severe hepatic disease.
• No known effect on the ability to drive or operate machinery.

Overdose Management
There is limited data on azithromycin overdose. Symptoms may include hearing loss, severe nausea, vomiting, and diarrhea. Treatment involves gastric lavage and supportive care.

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

Common Questions

• What is Zimax used for?
  Zimax is prescribed for respiratory, skin, soft tissue, and sexually transmitted infections.
• Can Zimax cause diarrhea?
  Yes, diarrhea is a possible side effect. Consult a doctor if it persists or worsens.
• Is Zimax safe?
  Yes, if used as prescribed by a physician.
• Is Zimax an antibiotic?
  Yes, it belongs to the macrolide class of antibiotics.
• What should I do if symptoms persist after taking Zimax?
  Consult your doctor if there is no improvement after 3 days of treatment.

Quick Tips

• Complete the full course of treatment even if you feel better.
• Take Zimax on an empty stomach for better absorption.
• Avoid antacids within 2 hours of taking Zimax.
• Report any severe diarrhea, allergic reactions, or unusual side effects to your doctor immediately.