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SENSORY ORGANS › OPHTHALMOLOGICALS › ANTIINFECTIVES › Antivirals
vidarabine
S01AD06
Forms & Strengths
- Ophthalmic ointment 5% (w/v)
- Intravitreal solution 100 mg/mL
- IV solution 5 mg/mL
Adult Dosing
- Herpes simplex keratitis: 5% ointment 5×/day for 7‑10 days
- CMV retinitis (off‑label): 100 mg intravitreal injection weekly
- Systemic HSV encephalitis (off‑label): 5 mg/kg IV q6h for 10‑14 days
Pediatric Dosing
- Herpes simplex keratitis: same topical regimen as adults
- Systemic infection: 5 mg/kg IV q6h (max 500 mg/day)
Indications
- Herpes simplex keratitis (primary & recurrent)
- Off‑label: CMV retinitis in immunocompromised
- Off‑label: HSV encephalitis and disseminated HSV
Mechanism of Action
- Adenosine analog phosphorylated to ara‑ATP
- Inhibits viral DNA polymerase and chain termination
- Incorporates into viral DNA causing faulty replication
Contraindications
- Known hypersensitivity to vidarabine or formulation excipients
- Severe ocular surface disease precluding ointment use
- Pregnancy Category C – avoid unless benefit outweighs risk
- Breastfeeding – caution; drug excreted in milk
Adverse Reactions
- Ocular burning, stinging, foreign‑body sensation
- Conjunctival hyperemia, eyelid edema
- Corneal epithelial toxicity, ulceration, stromal thinning
- Systemic neutropenia, thrombocytopenia, anemia
- Nausea, vomiting, elevated transaminases
- Renal dysfunction, increased serum creatinine
Drug Interactions
- Probenecid reduces renal clearance → increased toxicity
- Concurrent nephrotoxic agents (aminoglycosides, amphotericin B) ↑ renal risk
- Myelosuppressive drugs (e.g., cytarabine) additive marrow suppression
- Other antivirals (acyclovir, ganciclovir) – no major PK interaction but monitor for overlapping toxicity
Curated Content: Needs Vetting Before Put to Clinical Use