What is the recommended dose and duration of acyclovir for the treatment of Bell's palsy?

Acyclovir Dosing and Duration for Bell's Palsy

Acyclovir alone is not recommended for Bell's palsy treatment, but when used in combination with oral steroids, the recommended dose is 2000 mg/day (5 × 400 mg capsules) for 10 days. 1, 2

First-Line Treatment Recommendations

• Oral corticosteroids, not antivirals, are the primary recommended treatment for Bell's palsy and should be prescribed within 72 hours of symptom onset for patients 16 years and older 3, 2
• The recommended corticosteroid regimen is either prednisolone 50 mg daily for 10 days or prednisone 60 mg daily for 5 days followed by a 5-day taper 3, 4
• Corticosteroids significantly improve recovery rates (83% at 3 months and 94.4% at 9 months with prednisolone vs. 63.6% at 3 months and 81.6% at 9 months with placebo) 3, 1

Antiviral Therapy Considerations

• Antiviral therapy alone should not be prescribed for Bell's palsy as it shows no significant benefit compared to placebo 3, 2
• When used in combination with steroids, acyclovir may be given at 2000 mg/day (5 × 400 mg capsules) for 10 days 1, 5
• The evidence for combination therapy shows mixed results:
  • Some studies suggest a small additional benefit when antivirals are combined with steroids 6
  • A study by Hato et al. showed higher recovery rates with combination therapy (95.7%) compared to steroids alone (88.6%) 6
  • However, other large randomized trials found no significant additional benefit of acyclovir when added to prednisolone 1, 5

Timing of Treatment

• Both corticosteroids and antivirals (if used) should be initiated within 72 hours of symptom onset for maximum effectiveness 2, 4
• One study suggests that starting combination therapy within 3 days resulted in 100% recovery rate compared to 86.2% when started after 4 days 6
• The benefit of treatment after 72 hours is less clear and not well-supported by evidence 3, 7

Special Considerations

• Eye protection is essential for patients with impaired eye closure to prevent corneal damage 2, 8
• Patients should be reassessed or referred to a facial nerve specialist if they have:
  • New or worsening neurologic findings at any point 2, 4
  • Ocular symptoms developing at any point 2, 4
  • Incomplete facial recovery 3 months after initial symptom onset 2, 4

Common Pitfalls to Avoid

• Using antiviral therapy alone is ineffective and not recommended 3, 2
• Delaying treatment beyond 72 hours reduces effectiveness 2, 7
• Failing to provide adequate eye protection for patients with impaired eye closure 2, 8
• Neglecting to follow up patients with incomplete recovery after 3 months 2, 4