What is Acyclovir Buccal used for?
Last updated September 7, 2026.
Acyclovir buccal is a single-dose antiviral tablet you press onto your upper gum to treat recurrent cold sores on the lip and face in adults with a healthy immune system. It works best when you use it within one hour of the first tingling, itching, or burning and before a blister forms. One 50 mg tablet is the whole course: it sticks to the gum and releases acyclovir locally as it slowly dissolves, so there is no second dose for that outbreak. It shortens the episode but does not clear herpes simplex virus from your body or prevent future cold sores. It is not the right product for genital herpes, shingles, or chickenpox, which are treated with acyclovir taken by mouth or given by vein. If you get frequent outbreaks, have a weakened immune system, or the sore spreads toward your eye, talk with a clinician instead of self-treating.
What to do
- Treat at the first sign: Apply the tablet within one hour of tingling or burning and before the blister breaks out, since later use gives little benefit.
- Place it on the right side: Press the rounded side of the tablet against the upper gum above an incisor on the same side of your mouth as the cold sore, and hold it for 30 seconds.
- Leave it in place: Do not chew, crush, suck, or swallow the tablet; eat soft foods, drink fluids normally, and skip chewing gum until it dissolves.
- Know it is one dose: A single tablet is the full treatment for that outbreak, so do not add a second one if it falls out after six hours.
- Match the form to the infection: Buccal acyclovir is only for cold sores; genital herpes, shingles, and chickenpox need acyclovir by mouth or by vein.
- Ask a clinician when: Get medical advice if sores last longer than two weeks, keep coming back often, spread near your eye, or you have a weakened immune system.
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