What is the recommended dose of acyclovir for treating cold sores?

From the Guidelines

The recommended dose of acyclovir for treating cold sores is 400 mg taken orally three times a day for 5 days, as suggested by the most recent and highest quality study 1. This dose is effective in reducing the severity and duration of cold sore symptoms. Treatment should begin at the earliest sign of a cold sore (during the prodromal stage when tingling or burning occurs) for maximum effectiveness. Some key points to consider when treating cold sores with acyclovir include:

• Starting treatment early, ideally during the prodromal stage, for the best outcomes
• Completing the full course of medication, even if symptoms improve before completion
• Considering alternative or adjunct therapies, such as topical acyclovir cream (5%), for patients who prefer or require them
• Monitoring for potential side effects, such as headache, nausea, or dizziness, although these are generally mild
• Adjusting the dose for patients with kidney disease, as they may require a lower dose to avoid adverse effects
• Considering suppressive therapy for patients with severe or frequent outbreaks, which involves taking a lower dose daily to prevent recurrences, as noted in studies like 1 and 1.

From the Research

Acyclovir Dose for Cold Sores

• The recommended dose of acyclovir for treating cold sores is not directly stated in the provided studies, but we can look at the dosages used in similar contexts:
  • For herpes zoster, a study 2 found that oral acyclovir at a dosage of 800 mg five times per day for 10 days was effective in treating the condition.
  • Another study 3 used acyclovir at a dose of 800 mg orally, five times daily, for 7 or 21 days to treat acute herpes zoster.
• It's worth noting that valacyclovir, a prodrug of acyclovir, has been studied for the treatment of cold sores (herpes labialis) 4, 5. The dosages used in these studies were 2 g of valacyclovir twice daily for 1 day, or 2 g twice daily for 1 day followed by 1 g twice daily for 1 day.
• While the exact dosage of acyclovir for cold sores is not specified, we can infer that a dose of 800 mg five times daily may be effective based on its use in similar conditions 3, 2.
• However, it's essential to consult a healthcare professional for the correct diagnosis and treatment of cold sores, as they can provide personalized guidance on the appropriate dosage and duration of treatment.