What is the recommended loading dose of acyclovir for an oral herpes outbreak?

Recommended Loading Dose of Acyclovir for Oral Herpes Outbreak

For an oral herpes outbreak, the recommended loading dose of acyclovir is 400 mg orally 3 times daily for 5 days, or alternatively 200 mg orally 5 times daily for 5 days, or 800 mg orally twice daily for 5 days. 1

Treatment Regimens for Oral Herpes (Cold Sores)

• Oral antiviral medications are significantly more effective than topical formulations for treating cold sores 2
• Treatment should be initiated during the prodrome or within 2 days of onset of lesions for maximum benefit 1
• The recommended dosing options for recurrent episodes (including oral herpes outbreaks) are:
  • Acyclovir 200 mg orally 5 times a day for 5 days 1
  • Acyclovir 400 mg orally 3 times a day for 5 days 1
  • Acyclovir 800 mg orally 2 times a day for 5 days 1

Pharmacokinetics and Timing Considerations

• Peak plasma concentrations of acyclovir occur 1.5 to 2.5 hours after administration 3
• The oral bioavailability of acyclovir is relatively low at 15-30% 3
• The average plasma half-life is approximately 3 hours 3
• Early initiation of therapy is crucial for optimal effectiveness - treatment should begin within the first 72 hours of symptoms 4

Alternative Approaches

• Some evidence suggests that a single "stat" 800 mg dose of acyclovir taken at the first sensory signs of oral herpes may prevent lesions from appearing in many patients 5
• However, this single-dose approach is not part of standard guidelines and should be considered experimental 1

Special Considerations

• For immunocompromised patients, higher doses may be required:
  • Acyclovir 400 mg orally 3-5 times daily until clinical resolution 4, 2
• For HIV-infected patients, more aggressive therapy may be necessary with higher dosages 4, 2
• Patients should be counseled that acyclovir neither eradicates latent virus nor affects subsequent risk, frequency, or severity of recurrences after discontinuation 1, 4

Important Caveats

• Most immunocompetent patients with recurrent disease experience limited benefit from therapy 1
• Patients should be advised to abstain from activities that might spread the virus while lesions are present 1
• Higher doses of acyclovir (beyond standard recommendations) do not appear to provide additional clinical benefit but may increase the risk of adverse effects, particularly gastrointestinal symptoms 6