## Topical Drug of Choice for Trachoma (When Oral Therapy Unavailable) **Key Point:** When oral azithromycin is unavailable or contraindicated, **1% tetracycline eye ointment** is the preferred topical agent for active trachoma caused by *Chlamydia trachomatis*. ### Rationale for Tetracycline Ointment 1. **Mechanism:** Tetracycline is a broad-spectrum antibiotic with good intracellular penetration against chlamydia 2. **Dosing:** 1% ointment applied to both eyes 4 times daily for 6 weeks 3. **Efficacy:** Cure rate ~80–90% when compliance is adequate 4. **Accessibility:** Inexpensive and widely available in endemic regions 5. **Safety:** Well-tolerated topically; minimal systemic absorption in children ### Comparison of Topical Agents | Agent | Concentration | Efficacy vs Chlamydia | Duration | Cost | Use in Trachoma | |-------|---|---|---|---|---| | **Tetracycline** | 1% ointment | Excellent | 6 weeks | Low | **First-line topical** | | Erythromycin | 0.5% ointment | Good | 6 weeks | Moderate | Alternative (less preferred) | | Ciprofloxacin | 0.3% drops | Moderate | Prolonged | Moderate | Not preferred | | Chloramphenicol | 0.5% drops | Moderate | Prolonged | Low | Not preferred | **High-Yield:** Tetracycline ointment is the **WHO-recommended topical alternative** when oral azithromycin is unavailable. It remains the standard of care in resource-limited settings. **Clinical Pearl:** Tetracycline ointment should be applied to the conjunctival sac (not just the lid margin) to ensure adequate drug delivery. Patient/caregiver education on compliance is critical, as the 6-week regimen is lengthy. **Warning:** Erythromycin, while effective, is less commonly used for trachoma in current practice compared to tetracycline, despite similar efficacy. Do not confuse erythromycin (used for neonatal prophylaxis of ophthalmia neonatorum) with its role in chronic trachoma treatment.
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