What is the best antiviral for Bell's palsy?

Antivirals for Bell's Palsy

Antivirals should not be used as monotherapy for Bell's palsy, but may be offered in combination with oral steroids within 72 hours of symptom onset as an optional treatment. 1, 2

First-Line Treatment Approach

• Oral corticosteroids are the primary evidence-based treatment for Bell's palsy and should be prescribed within 72 hours of symptom onset 2, 3
• The recommended corticosteroid regimen is prednisolone 50 mg daily for 10 days or prednisone 60 mg daily for 5 days followed by a 5-day taper 2, 3
• Antiviral therapy alone is ineffective and should NOT be prescribed for Bell's palsy 1, 2

Antiviral Options as Adjunctive Therapy

When considering combination therapy with steroids, the following antivirals have been studied:

• Valacyclovir: 1000 mg three times daily for 7 days has shown some benefit in combination with prednisolone 4
  • One study showed higher complete recovery rates with valacyclovir plus prednisolone (96.5%) compared to prednisolone alone (89.7%) 4
• Famciclovir: Has shown some benefit in smaller studies when combined with prednisolone 1
• Acyclovir: Some evidence suggests benefit when combined with prednisone if started within 72 hours 5

Evidence Quality and Recommendations

• The American Academy of Otolaryngology-Head and Neck Surgery gives combination antiviral therapy an "Option" level recommendation (Grade B evidence) 1
• The benefit of adding antivirals to steroids is small but real, while the risks are minimal 1
• A 2019 Cochrane review found that antivirals plus corticosteroids may have little or no effect on recovery rates compared to corticosteroids alone, but may reduce long-term sequelae like motor synkinesis 6

Clinical Decision Algorithm

1. For all patients with Bell's palsy presenting within 72 hours of symptom onset:

   • Start oral corticosteroids immediately 2, 3
   • Consider adding an antiviral (preferably valacyclovir) 1, 4

2. For patients presenting after 72 hours:

   • Focus on eye protection rather than antivirals 7
   • Monitor for recovery and refer if incomplete recovery persists at 3 months 3, 7

3. For patients with severe Bell's palsy (complete facial paralysis):

   • Combination therapy may be more beneficial, though evidence is limited 1, 4

Important Considerations and Pitfalls

• Antivirals alone have been proven ineffective and should never be prescribed without steroids 1, 6
• Delaying treatment beyond 72 hours significantly reduces effectiveness of both steroids and antivirals 7
• Eye protection is essential for all patients with impaired eye closure, regardless of medication choice 1, 3
• The benefit of antiviral therapy is modest at best, and the decision to use combination therapy should involve shared decision making 1

Special Populations

• For children, evidence for both steroids and antivirals is less conclusive as they have higher rates of spontaneous recovery 2, 3
• For pregnant women, treatment should be carefully considered with individualized assessment of benefits and risks 3
• Elderly patients may benefit more from combination therapy, with one study showing significantly better outcomes in patients over 60 years treated with valacyclovir and prednisone 8

In summary, while no antiviral can be considered "best" as monotherapy for Bell's palsy, valacyclovir has the strongest evidence as an adjunct to corticosteroid therapy when initiated within 72 hours of symptom onset.