What happens if you miss a dose of Acyclovir Buccal?
Last updated September 7, 2026.
**If you miss acyclovir buccal, you can miss its early treatment window; do not double your dose.** You use acyclovir buccal as a single dose for a cold sore episode, so there is no routine next dose. Apply it within 1 hour of your first tingling, itching, redness, or burning, before a cold sore appears. If you miss that window or already have a visible sore, ask your pharmacist or prescribing clinician what to do. Keep your prescribed tablet accessible and note the application time so you can follow the replacement instructions if it comes loose.
What to do
- **Check your formulation:** Confirm that you have the buccal tablet, since swallowed acyclovir has different dosing instructions.
- **Act early:** Apply your prescribed tablet within 1 hour of your first symptoms, before a cold sore appears.
- **Ask about a late start:** Contact your pharmacist or prescribing clinician if you missed the early treatment window.
- **Record the time:** Note when you apply your tablet so you know whether the 6-hour replacement window has passed.
- **Let it dissolve:** Leave your tablet on your upper gum without chewing, crushing, sucking, or intentionally swallowing it.
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