Azithromycine

# Azithromycine ## Overview - **Classification**: Macrolide Antibiotic - **Mechanism**: Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, thereby blocking translocation of peptides. ## Primary Indications 1. **Community-Acquired Pneumonia (CAP)** - Caused by susceptible organisms 2. **Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB)** - Susceptible organisms 3. **Streptococcal Pharyngitis** - Alternative for penicillin-allergic patients 4. **Acute Bacterial Sinusitis** - Susceptible organisms 5. **Uncomplicated Skin and Skin Structure Infections** - Susceptible organisms 6. **Urethritis/Cervicitis** - Due to Chlamydia trachomatis ## Adult Dosing ### Standard Dosing **Community-Acquired Pneumonia, ABECB, Acute Bacterial Sinusitis, Skin Infections** - **Dose**: **500 mg** - **Frequency**: Once on Day 1, then **250 mg** daily - **Route**: Oral - **Duration**: Total 3-5 days **Streptococcal Pharyngitis (alternative)** - **Dose**: **500 mg** - **Frequency**: Once daily - **Route**: Oral - **Duration**: 3 days **Uncomplicated Chlamydia trachomatis (Urethritis/Cervicitis)** - **Dose**: **1 gram** (1000 mg) - **Frequency**: Single dose - **Route**: Oral ### Dose Adjustments - **Renal Impairment**: No dosage adjustment needed. - **Hepatic Impairment**: Use with caution. Not recommended in severe hepatic impairment. - **Elderly Patients**: No specific dose adjustment. Monitor for QTc prolongation. ## Pediatric Dosing ### Neonates (0-28 days) - **Special Notes**: Not routinely recommended. Use only for specific indications like Chlamydial conjunctivitis/pneumonia. - **Chlamydial Conjunctivitis/Pneumonia**: - **Dose**: **20 mg/kg/day** - **Frequency**: Once daily - **Route**: Oral - **Duration**: 3 days - **Maximum**: Not to exceed adult dose. - **Special Notes**: Consider alternative treatments due to potential for infantile hypertrophic pyloric stenosis (IHPS). ### Infants (1-12 months) - **Acute Otitis Media**: - **Dose**: **30 mg/kg** as a single dose OR **10 mg/kg** once daily for 3 days OR **10 mg/kg** on Day 1, then **5 mg/kg** daily for 4 days. - **Frequency**: As above - **Route**: Oral - **Maximum**: **500 mg** (Day 1), **250 mg** (subsequent days) - **Pharyngitis/Tonsillitis (Streptococcal)**: - **Dose**: **12 mg/kg** - **Frequency**: Once daily - **Route**: Oral - **Duration**: 5 days - **Maximum**: **500 mg/day** ### Children (1-12 years) - **Acute Otitis Media**: - **Dose**: **30 mg/kg** as a single dose OR **10 mg/kg** once daily for 3 days OR **10 mg/kg** on Day 1, then **5 mg/kg** daily for 4 days. - **Frequency**: As above - **Route**: Oral - **Maximum**: **500 mg** (Day 1), **250 mg** (subsequent days) - **Pharyngitis/Tonsillitis (Streptococcal)**: - **Dose**: **12 mg/kg** - **Frequency**: Once daily - **Route**: Oral - **Duration**: 5 days - **Maximum**: **500 mg/day** ### Adolescents (13-18 years) - **Dose**: Refer to adult dosing guidelines. - **Maximum**: Adult dose. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to azithromycin, erythromycin, or any macrolide/ketolide. - **Absolute**: History of cholestatic jaundice/hepatic dysfunction associated with prior azithromycin use. ### Common Adverse Effects - **Very Common (>10%)**: Diarrhea, Abdominal pain - **Common (1-10%)**: Nausea, Vomiting, Headache, Flatulence - **Serious but Rare**: QT prolongation (arrhythmias), C. difficile-associated diarrhea, Hepatotoxicity (including hepatic failure), Angioedema, Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN). ### Key Drug Interactions - **Antacids (containing Aluminum or Magnesium)**: Decreased azithromycin peak plasma levels. Administer azithromycin at least **1 hour before or 2 hours after** antacids. - **QT-prolonging drugs**: Increased risk of Torsades de Pointes. Avoid co-administration with Class IA/III antiarrhythmics, antipsychotics, antidepressants. - **Warfarin**: Enhanced anticoagulant effect. Monitor **INR** closely. - **Digoxin**: Increased digoxin levels. Monitor **digoxin levels**. - **Cyclosporine**: Increased cyclosporine levels. Monitor **cyclosporine levels**. ## Monitoring & Follow-up - **Before Treatment**: Baseline ECG if risk factors for QTc prolongation (e.g., hypokalemia, bradycardia, concurrent QTc-prolonging drugs). Baseline LFTs if pre-existing hepatic disease. - **During Treatment**: Monitor for signs of hepatotoxicity (dark urine, jaundice, fatigue), severe diarrhea (C. diff), or allergic reactions. - **Clinical Signs**: Palpitations, dizziness (QTc prolongation), rash, difficulty breathing (allergic reaction), severe abdominal pain (C. diff). ## Clinical Pearls - 💡 **Administration**: Can be taken with or without food. Take with food if GI upset occurs. - 💡 **Suspension Storage**: Oral suspension does not require refrigeration. Stable for 10 days. - 💡 **QTc Risk**: Counsel patients on symptoms of arrhythmia (dizziness, palpitations). Avoid in patients with congenital long QT syndrome. - 💡 **Completing Course**: Emphasize importance of completing the full course even if symptoms improve. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.