What is the recommended dose of acyclovir (antiviral medication) for the treatment of Bell's palsy?

Acyclovir Dosing for Bell's Palsy Treatment

For Bell's palsy, the recommended antiviral regimen is acyclovir 400 mg five times per day for 10 days, but it should only be used in combination with corticosteroids, never alone. 1

First-Line Treatment Approach

• Oral corticosteroids are the primary treatment for Bell's palsy and should be prescribed within 72 hours of symptom onset for patients 16 years and older 2, 3
• 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 2, 3
• Antiviral therapy alone should NOT be prescribed for Bell's palsy as it is ineffective 2, 3, 1

Combination Therapy with Acyclovir

• If considering combination therapy, acyclovir should be dosed at 400 mg five times per day for 10 days (total daily dose 2000 mg) 2, 1
• Alternatively, valacyclovir can be used at 1 g three times per day for 7 days 1
• Combination therapy may be offered within 72 hours of symptom onset as an option 3
• Some evidence shows slightly higher complete recovery rates with combination therapy (96.5%) compared to steroids alone (89.7%) 3

Timing of Treatment

• All treatment (steroids alone or combination therapy) must be initiated within 72 hours of symptom onset for maximum efficacy 2, 4
• Treatment started after 72 hours has less clear benefit and is not supported by high-quality evidence 4
• One study showed 100% recovery rate when combination therapy was started within 3 days of onset, versus 86.2% when started after 4 days 5

Evidence for Treatment Efficacy

• Strong evidence supports corticosteroid use, with 83% recovery at 3 months with prednisolone vs 63.6% with placebo 2, 6
• Evidence for acyclovir alone shows no significant benefit (71.2% recovery for acyclovir vs 75.7% for no acyclovir) 6, 7
• The benefit of adding acyclovir to corticosteroids is small but may reduce rates of synkinesis 1

Important Considerations and Pitfalls

• Never prescribe antiviral therapy alone for Bell's palsy as multiple studies have shown it to be ineffective 2, 3, 7
• Do not delay treatment beyond 72 hours as this significantly reduces effectiveness 4
• Always implement eye protection for patients with impaired eye closure to prevent corneal damage 2, 4
• Remember that approximately 70% of Bell's palsy patients with complete paralysis recover facial function completely within 6 months even without treatment 4

Special Populations

• For children, evidence for medication use is less conclusive as they show higher rates of spontaneous recovery than adults 2, 4
• For pregnant women, treatment should be carefully considered with individualized assessment of benefits and risks 4