Vibramycin

# Vibramycin ## Overview - **Classification**: Tetracycline antibiotic - **Mechanism**: Reversibly binds to the 30S ribosomal subunit, inhibiting bacterial protein synthesis. ## Primary Indications 1. **Bacterial Infections**: Respiratory, urinary, skin/soft tissue infections. 2. **Sexually Transmitted Infections**: Chlamydia, gonorrhea, syphilis (alternative). 3. **Lyme Disease**: Early-stage treatment and prophylaxis after tick bite. 4. **Malaria Prophylaxis/Treatment**: For susceptible strains. 5. **Acne**: Moderate to severe inflammatory acne. ## Adult Dosing ### Standard Dosing **General Bacterial Infections (e.g., Respiratory, Skin)** - **Dose**: **100 mg** - **Frequency**: Every 12 hours (BID) - **Route**: Oral (PO) or Intravenous (IV) - **Duration**: Typically 7-14 days depending on infection severity. **Chlamydia Trachomatis (uncomplicated urethral, endocervical, rectal)** - **Dose**: **100 mg** - **Frequency**: BID - **Route**: PO - **Duration**: 7 days **Malaria Prophylaxis** - **Dose**: **100 mg** - **Frequency**: Once daily - **Route**: PO - **Duration**: Start 1-2 days before travel, continue daily during travel, and for 4 weeks after leaving endemic area. ### Dose Adjustments - **Renal Impairment**: No dose adjustment typically needed. Doxycycline is primarily eliminated via non-renal routes. - **Hepatic Impairment**: Use with caution in severe hepatic dysfunction; monitor liver function tests. - **Elderly Patients**: No specific dose adjustment needed, but monitor for adverse effects, especially GI. ## Pediatric Dosing ### Neonates (0-28 days) - **Generally Avoided**: Due to risk of permanent tooth discoloration and enamel hypoplasia. - **Special Notes**: Only consider for severe or life-threatening infections (e.g., Rocky Mountain Spotted Fever, anthrax exposure) where other options are contraindicated or ineffective. - **Dose (if indicated)**: **2.2 mg/kg/dose** - **Frequency**: Every 12 hours - **Maximum**: **100 mg/dose** ### Infants (1-12 months) - **Generally Avoided**: Due to risk of permanent tooth discoloration and enamel hypoplasia. - **Special Notes**: Similar to neonates, reserved for severe infections with limited alternatives. - **Dose (if indicated)**: **2.2 mg/kg/dose** - **Frequency**: Every 12 hours - **Maximum**: **100 mg/dose** ### Children (1-12 years) - **Generally Avoided < 8 years**: Due to risk of permanent tooth discoloration and enamel hypoplasia. - **Used with caution < 8 years for severe infections**: E.g., Rocky Mountain Spotted Fever (drug of choice), anthrax. - **Dose (< 8 years, if indicated for severe infection)**: **2.2 mg/kg/dose** - **Frequency**: Every 12 hours - **Maximum**: **100 mg/dose** - **Children ≥ 8 years**: - **Dose**: **2.2 mg/kg** (Loading dose **4.4 mg/kg** for severe infections on day 1, then **2.2 mg/kg** daily) - **Frequency**: Once daily (or BID for loading dose) - **Maximum**: **200 mg/day** (or **100 mg/dose** if BID) ### Adolescents (13-18 years) - **Dose**: Typically follows adult dosing guidelines. - **Maximum**: **200 mg/day** (or **100 mg/dose** if BID) ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to doxycycline or other tetracyclines. - **Absolute**: Pregnancy (Category D) and Breastfeeding (relative, due to teeth effects). - **Relative**: Children under 8 years of age (due to tooth discoloration), unless benefit outweighs risk. ### Common Adverse Effects - **Very Common (>10%)**: Photosensitivity (sunburn-like reaction). - **Common (1-10%)**: Nausea, vomiting, diarrhea, esophageal irritation/ulceration, vaginal candidiasis. - **Serious but Rare**: Pseudotumor cerebri (idiopathic intracranial hypertension), severe dermatologic reactions (e.g., SJS), C. difficile-associated diarrhea (CDAD). ### Key Drug Interactions - **Antacids, Iron, Calcium, Magnesium, Bismuth**: Decreased doxycycline absorption. Separate administration by **2-3 hours**. - **Oral Contraceptives**: May decrease efficacy (though controversial, counsel patients). Consider alternative contraception. - **Warfarin**: May potentiate anticoagulant effect. Monitor INR closely. - **Penicillins**: May interfere with bactericidal action. Avoid concurrent use if possible. ## Monitoring & Follow-up - **Before Treatment**: Baseline renal/hepatic function for prolonged therapy. - **During Treatment**: Monitor for signs of photosensitivity, GI upset, or C. difficile infection. - **Clinical Signs**: Watch for headache, blurred vision (pseudotumor cerebri symptoms). ## Clinical Pearls - 💡 **Administration**: Take with a **full glass of water** and remain **upright for 30-60 minutes** to prevent esophageal irritation and ulceration. - 💡 **Food Interaction**: Can be taken with food (non-dairy) if stomach upset occurs. Avoid dairy products, antacids, and iron supplements within **2 hours** of dose. - 💡 **Sun Sensitivity**: Advise patients to use **sunscreen** and wear protective clothing due to high risk of photosensitivity. - 💡 **Pediatric Use**: Emphasize rationale for use in children <8 years old (e.g., RMSF) and discuss tooth discoloration risk with parents. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.