Azithromycin

Azithromycin

Name

• Generic: Azithromycin
• Brand Names: Zithromax, Azax, Azee, Zmax
• Common Forms: Tablets, suspension, IV

Classification

• Class: Macrolide antibiotic
• Mechanism: Inhibits bacterial protein synthesis by binding to 50S ribosomal subunit

Indications

• Respiratory tract infections (e.g., bronchitis, pneumonia)
• ENT infections (e.g., pharyngitis, sinusitis, otitis media)
• Skin and soft tissue infections
• Sexually transmitted infections (e.g., chlamydia, gonorrhoea)
• Mycobacterium avium complex (MAC) prophylaxis
• Traveller’s diarrhoea (off-label)
• COVID-19 (off-label in some protocols – controversial)

Dose

• Adults:
  • Typical: 500 mg once on Day 1, then 250 mg once daily for 4 days
  • STIs: 1g (1000 mg) single dose
  • MAC prophylaxis: 1200 mg once weekly
• Children:
  • 10 mg/kg on Day 1, then 5 mg/kg once daily for 4 days
  • Maximum: Usually 500 mg/day

Side Effects

• Common:
  • Nausea, diarrhoea, abdominal pain
  • Headache
• Less Common:
  • Taste disturbance, flatulence
• Rare but Serious:
  • QT prolongation → arrhythmia
  • Hepatotoxicity
  • Severe allergic reactions (anaphylaxis, SJS)
  • Clostridium difficile-associated diarrhoea

Interactions

• QT-prolonging agents (e.g., amiodarone, fluoroquinolones) → additive effect
• Antacids (aluminium/magnesium) → reduce absorption
• Warfarin → enhanced anticoagulation effect
• Cyclosporine, digoxin → levels may increase

Warnings

• QT prolongation risk
• Hepatotoxicity risk
• Potential for serious allergic reactions
• Not suitable for treating syphilis

Cautions

• Heart conditions (arrhythmias, bradycardia, QT issues)
• Liver dysfunction
• Renal impairment (use with care if severe)
• Elderly (higher risk of cardiac effects)

Pregnancy

• Generally considered safe
• Classified as Pregnancy Category B (US)
• No known teratogenic effects

Hepatic

• Caution in liver impairment
• Monitor LFTs in prolonged use

Renal

• No dose adjustment usually required in mild/moderate disease
• Caution in severe impairment

Contraindications

• Known hypersensitivity to azithromycin or macrolides
• History of cholestatic jaundice/hepatitis with prior azithromycin use

Counselling

• Take 1 hour before or 2 hours after meals
• Finish full course even if feeling better
• Avoid antacids 2 hours before/after dose
• May cause diarrhoea – report persistent/watery stools
• Report palpitations or fainting

Monitoring

• ECG if risk factors for QT prolongation
• Liver function in prolonged use
• Signs of superinfection (e.g., fungal or C. diff)
• INR if on warfarin

Use in Pregnancy

• Acceptable if clearly needed
• No fetal harm observed in studies

Use in Children

• Approved for use
• Dosing based on weight
• Widely used for AOM, pneumonia, strep throat

Use in Elderly

• Use with caution
• Monitor ECG and electrolytes

Costs, Brands, Manufacturer

Brand	Manufacturer	Approx. Cost (USD)
Zithromax	Pfizer	$20–$30 (5-day pack)
Azithral	Alembic/Abbott	$4–$10 (generic)
Azee	Cipla	$5–$12

FAQs – Azithromycin

1. Is azithromycin a strong antibiotic?
   – Yes, broad-spectrum and effective against many bacteria, especially respiratory pathogens.
2. Can I take it with food?
   – Best taken on an empty stomach, but can be taken with food to reduce stomach upset.
3. Does it treat COVID-19?
   – No longer recommended; not proven to reduce mortality or severity.
4. How quickly does it work?
   – Symptom relief usually starts within 24–48 hours.
5. Can it be used for sore throat?
   – Yes, especially if caused by bacterial infection (e.g., strep throat).
6. What should I avoid while taking azithromycin?
   – Avoid antacids near dosing time and alcohol if causing GI symptoms.
7. Can it cause diarrhoea?
   – Yes, common. Severe diarrhoea may signal C. difficile – seek medical advice.
8. Does it affect heart rhythm?
   – Rarely, it can prolong QT interval, especially in those with risk factors.
9. Can I take it with other antibiotics?
   – Sometimes, but combinations must be prescribed carefully to avoid interactions.
10. How is it different from amoxicillin?
    – Azithromycin is macrolide (protein synthesis inhibitor); amoxicillin is a penicillin (cell wall synthesis inhibitor). Both are used in respiratory infections, but resistance patterns differ.