Vibramycin
Vibramycin
Generic Name
Vibramycin
Mechanism
- Binds 30S ribosomal subunit of susceptible bacteria, blocking attachment of aminoacyl‑tRNA.
- Inhibits peptide bond formation → ↓ bacterial protein synthesis.
- Activity depends on the presence of divalent cations; chelation (e.g., calcium) reduces absorption.
Pharmacokinetics
| Parameter | Approximate Values |
| Absorption | 70–80 % orally; diminished in presence of calcium or magnesium. |
| Distribution | Widely distributed; protein binding ~50 %. Concentrates in bone, CSF, tears, saliva. |
| Metabolism | Minimal hepatic metabolism; predominantly excreted unchanged. |
| Excretion | 70–80 % unchanged in urine; half‑life ~8–12 h (oral), 2–5 h (IV). |
Indications
- Respiratory tract infections (e.g., *Mycoplasma pneumoniae*, *Chlamydophila pneumoniae*).
- Skin and soft‑tissue infections (impetigo, acne vulgaris).
- Urinary tract infections caused by susceptible organisms.
- Ocular infections (conjunctivitis, blepharitis).
- Tick‑borne illnesses (e.g., Rocky Mountain spotted fever, ehrlichiosis).
- Travel‑related enteric fever prophylaxis.
*Note:* Use is limited in children <8 y, pregnant women (3rd trimester), and patients with photosensitivity.
Contraindications
- Pregnancy (particularly 3rd trimester).
- Children under 8 y (teeth discoloration, dental enamel suppression).
- Concurrent use with antacids, dairy, or fortified cereals (chelation).
- Ophthalmic use with eye infections—monitor for mucous membrane irritation.
- Concurrent liver disease (rare, but monitor transaminases).
- Suspected hypersensitivity to tetracyclines.
Dosing
| Indication | Adult Dose (oral) | Adult Dose (IV) | Duration |
| Respiratory infections | 250 mg PO q6 h (or 500 mg q12 h) | 10 mg/kg q6 h (max 500 mg q6 h) | 7–10 days |
| Acne vulgaris | 1000 mg PO once daily | — | 6–12 weeks |
| Tick‑borne diseases | 1000 mg PO once daily for 10–14 days | 10 mg/kg q6 h (first 24 h) | 10–14 days |
| Urinary tract infections | 500 mg PO q6 h | 10 mg/kg q6 h (max 500 mg q6 h) | 7–10 days |
• Take on an empty stomach 1 h before/after meals.
• Avoid dairy or calcium‑rich products within 2 h of dosing.
• If oral intolerance, consider IV formulation.
Adverse Effects
Common
• Gastrointestinal upset (nausea, vomiting, diarrhea).
• Photosensitivity (sunburn, rash).
• Oral/dental staining.
• Taste disturbance.
Serious
• Hypersensitivity (urticaria, angioedema).
• Intracranial hypertension (headache, vomiting).
• Tendon rupture (rare, akin to fluoroquinolones).
• Clostridioides difficile colitis (secondary to microbiome disruption).
Monitoring
- Baseline CBC, LFTs, electrolytes for patients on prolonged therapy.
- Renal function if high doses IV.
- Serum calcium in patients on calcium supplements.
- Skin inspection for photosensitivity reactions.
- Dental review in pediatric patients.
Clinical Pearls
- Take at least 1 h before or after calcium‑rich foods to avoid chelation and absorption loss.
- Use broad‑spectrum coverage: Vibramycin penetrates bone and CSF; useful when *Staphylococcus*, *Pseudomonas*, or *Corynebacterium* are resistant.
- Adjunctive therapy in acne: combine with topical benzoyl peroxide to reduce resistance.
- Photosensitivity check: patients on Vibramycin should wear UVA‑blocking sunglasses and reapply SPF ≥30 sunblock throughout the day.
- Pregnancy data: although contraindicated in 3rd trimester, some case reports reveal safe use in 1st/2nd trimester when benefits outweigh risks; always use with caution.
- Drug interactions: avoid antacids, Zinc, Iron, Aluminum, and Calcium within 2 h of dosing due to complexation.
- Renal impairment: dose adjustment may not be necessary if therapy is <7 days, but monitor creatinine closely.
- Pediatric dosing schedule: 10 mg/kg q6 h (max 250 mg) for 7–14 days; avoid if possible due to staining risk.
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• *All information is current as of 2026; consult the latest prescribing information or drug references before clinical use.*