Azithro

# Azithro ## Overview - **Classification**: Macrolide antibiotic - **Mechanism**: Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing peptide translocation. ## Primary Indications 1. **Community-Acquired Pneumonia (CAP)**: Treatment of mild-to-moderate CAP. 2. **Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB)**: Treatment for bacterial exacerbations. 3. **Streptococcal Pharyngitis**: Alternative for penicillin-allergic patients with Group A strep. 4. **Chlamydia Trachomatis Infections**: Uncomplicated urethral, endocervical, or rectal infections. 5. **Mycobacterium Avium Complex (MAC)**: Prophylaxis and treatment in HIV-infected patients. ## Adult Dosing ### Standard Dosing **Community-Acquired Pneumonia (CAP), Pharyngitis/Tonsillitis, Skin/Soft Tissue Infections** - **Dose**: Day 1: **500 mg** - **Frequency**: Once daily - **Route**: Oral (PO) - **Duration**: Days 2-5: **250 mg** daily for a total of 5 days. **Acute Bacterial Exacerbation of Chronic Bronchitis (ABECB)** - **Dose**: **500 mg** - **Frequency**: Once daily - **Route**: Oral (PO) - **Duration**: Total 3 days **Chlamydia Trachomatis (Uncomplicated Urethritis/Cervicitis)** - **Dose**: **1000 mg** (1 gram) - **Frequency**: Single dose - **Route**: Oral (PO) **Mycobacterium Avium Complex (MAC) Prophylaxis** - **Dose**: **1200 mg** - **Frequency**: Once weekly - **Route**: Oral (PO) ### Dose Adjustments - **Renal Impairment**: No dosage adjustment needed for mild to moderate impairment (CrCl >10 mL/min). Use with caution in severe renal impairment. - **Hepatic Impairment**: No dosage adjustment needed for mild to moderate impairment. Use with caution in severe hepatic dysfunction. - **Elderly Patients**: No specific dose adjustment based on age. Monitor for QTc prolongation. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: Not routinely recommended. - **Special Notes**: High risk of Infantile Hypertrophic Pyloric Stenosis (IHPS). Use only if no alternative. Consult infectious disease. ### Infants (1-12 months) - **Indication**: Acute Otitis Media (AOM) - **Dose**: **10 mg/kg** - **Frequency**: Once daily for 3 days - **Maximum**: **500 mg/day** ### Children (1-12 years) - **Indication**: Acute Otitis Media (AOM) - **Dose**: **30 mg/kg** as a single dose OR **10 mg/kg** once daily for 3 days. - **Maximum**: Single dose **1500 mg**. Daily **500 mg**. - **Indication**: Pharyngitis/Tonsillitis (Group A Strep) - **Dose**: **12 mg/kg** - **Frequency**: Once daily for 5 days - **Maximum**: **500 mg/day** ### Adolescents (13-18 years) - **Dose**: Follows adult dosing guidelines. - **Maximum**: Adult maximum doses apply. ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to azithromycin, erythromycin, or any macrolide. - **Absolute**: History of cholestatic jaundice/hepatic dysfunction associated with prior azithromycin use. - **Relative**: History of QTc prolongation, hypokalemia, or hypomagnesemia. ### Common Adverse Effects - **Very Common (>10%)**: Diarrhea, Nausea, Abdominal pain - **Common (1-10%)**: Vomiting, Headache, Flatulence, Dizziness - **Serious but Rare**: Torsades de Pointes, Cholestatic hepatitis, Stevens-Johnson syndrome, Angioedema, IHPS (in neonates/infants). ### Key Drug Interactions - **Antacids (Mg/Al)**: Decreased azithromycin absorption. Administer azithromycin **1 hr before or 2 hrs after** antacids. - **QTc prolonging drugs (e.g., Amiodarone, Fluoroquinolones, Class IA/III Antiarrhythmics)**: Increased risk of QTc prolongation and Torsades de Pointes. Avoid concomitant use. - **Warfarin**: Potential to potentiate anticoagulant effect. Monitor INR closely. - **Digoxin**: May increase digoxin levels. Monitor digoxin concentrations. - **Nelfinavir**: Increased azithromycin serum concentrations. Monitor for adverse effects. ## Monitoring & Follow-up - **Before Treatment**: Assess for history of macrolide allergy or QTc prolongation risk factors. - **During Treatment**: Monitor for signs of C. difficile infection (CDI) (e.g., severe diarrhea). - **Clinical Signs**: Watch for persistent infection symptoms, allergic reactions (rash, swelling), or signs of liver injury (jaundice). ## Clinical Pearls - 💡 **Tip 1**: Azithromycin has a long tissue half-life, allowing for short, convenient dosing regimens. - 💡 **Tip 2**: Oral suspension should be shaken well before administration. - 💡 **Tip 3**: May be taken with or without food. Taking with food may reduce GI upset. - 💡 **Tip 4**: Counsel patients to complete the entire prescribed course of therapy. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.