This medication is used to treat "cold sores/fever blisters" (herpes labialis). It can speed up healing of the sores and decrease symptoms (such as tingling, pain, burning, itching). Penciclovir belongs to a class of medications known as antivirals. It works by stopping the growth of the virus. This medication does not cure herpes, and it does not prevent passing the infection to someone else. It does not prevent future occurrences.

Use this medication at the first sign of infection (such as tingling, burning, redness, or sores). Wash your hands with soap and water before and after applying this medication. Clean and dry the affected areas before applying the medication. Apply a thin layer of penciclovir cream to completely cover the area of the cold sore or the area of tingling/itching/redness/swelling, and rub in gently. Apply the cream as directed by your doctor, usually every 2 hours (except during sleep) for 4 days.

Apply to skin only. Do not apply this medication in or near the eyes since this medication can irritate the eyes. If you do get medication in your eyes, flush with plenty of water. Do not apply inside the mouth or nose.

Dosage is based on your medical condition and response to treatment. Do not use this drug more often or for longer than prescribed.

Use this medication regularly to get the most benefit from it. This medication works best when the amount of drug absorbed by the skin stays at a constant level. Use this drug at evenly spaced intervals. To help you remember, use it at the same times each day.

Cold sores (herpes) can spread easily. Penciclovir cream does not prevent the spread of herpes. Avoid close physical contact with others (such as kissing) during an outbreak until the cold sores have completely healed. Also, try not to touch the cold sore, and wash your hands if you do touch the cold sore.

Tell your doctor if your condition lasts or gets worse after treatment is finished.

Redness, burning, stinging, or numbness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using penciclovir, tell your doctor or pharmacist if you are allergic to it; or to famciclovir; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history.

Tell your doctor if you are pregnant before using this medication.

This medication does not pass into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

This medicine may be harmful if swallowed. If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Do not share this medication with others. Doing so may spread the infection.

Cold sore outbreaks can be triggered by many factors such as stress, hormonal changes (such as pregnancy, menstrual period), injury/surgery on the mouth (such as dental work), tiredness, sunlight, cold weather, or fever/cold/flu.

If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Use your next dose at the regular time. Do not double the dose to catch up.

Store this medication at room temperature. Firmly screw the cap back on the tube of medication after each use. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.