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Generic Name: penciclovir topical (pen SYE kloe veer TOP ik al)
Brand Name: Denavir

Medically reviewed on November 17, 2016

What is penciclovir topical?

Penciclovir is an antiviral medication.

Penciclovir topical (for the skin) is used to treat cold sores on the lips that are caused by the herpes simplex virus. This medicine is for adults and children who are at least 12 years old.

Penciclovir topical is not a cure for cold sores and you may continue to have them in the future.

Penciclovir topical may also be used for purposes not listed in this medication guide.

Important Information

Do not apply penciclovir topical to the inside of the nose or in or near the eyes.

Before taking this medicine

You should not use penciclovir topical if you are allergic to it.

Penciclovir topical is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant.

It is not known whether penciclovir topical passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Penciclovir topical is not approved for use by anyone younger than 12 years old.

How should I use penciclovir topical?

Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Do not take by mouth. Topical medicine is for use only on the lips and face. If this medicine gets in your nose or mouth, rinse with water.

Penciclovir topical should be used to treat cold sores on the lips and face only.

For best results, start using penciclovir as soon as possible after you notice symptoms of a developing cold sore (tingling, redness, itching, or a bump).

Wash your hands before and after applying penciclovir topical. Also wash and dry the skin area to be treated.

Apply a thin layer of penciclovir to the cold sore area. Use enough medicine to cover only the cold sore itself, or the skin where you feel tingling or early symptoms of a developing cold sore. Rub in gently until the medicine disappears.

Do not apply penciclovir topical to the inside of your nose or near your eyes.

Penciclovir topical is usually applied every 2 hours throughout the day for 4 days in a row. Follow your doctor's dosing instructions very carefully.

Call your doctor if your symptoms do not improve, or if they get worse.

Store penciclovir topical at room temperature away from moisture and heat.

What happens if I miss a dose?

Apply the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next dose. Do not use extra medicine to make up the missed dose.

What happens if I overdose?

An overdose of penciclovir topical is not expected to be dangerous. Seek emergency medical attention or call the Poison Help line at 1-800-222-1222 if anyone has accidentally swallowed the medication.

What should I avoid while using penciclovir topical?

Rinse with water if this medicine gets in your eyes.

Penciclovir topical side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have severe skin redness, itching, rash, or pain after applying this medicine.

Common side effects may include:

  • numbness or tingling where the medicine was applied;

  • headache; or

  • changes in your sense of taste.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect penciclovir topical?

It is not likely that other drugs you take orally or inject will have an effect on topically applied penciclovir. But many drugs can interact with each other. Tell each of your health care providers about all medicines you use, including prescription and over-the-counter medicines, vitamins, and herbal products.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.