Medically reviewed by A Ras MD.
What is penciclovir used for?
Penciclovir is a prescription medicine that is used to treat cold sores.
DENAVIR (penciclovir) cream 1% contains penciclovir, an antiviral agent active against herpes viruses. DENAVIR is available for topical administration as a 1% white cream. Each gram of DENAVIR contains 10 mg of penciclovir and the following inactive ingredients: cetostearyl alcohol, mineral oil, polyoxyl 20 cetostearyl ether, propylene glycol, purified water and white petrolatum.
Chemically, penciclovir is known as 9-[4-hydroxy-3-(hydroxymethyl)butyl] guanine. Its molecular formula is C10H15N5O3; its molecular weight is 253.26. It is a synthetic acyclic guanine derivative and has the following structure:
Figure 1: Structural Formula of Penciclovir
Penciclovir is a white to pale yellow solid. At 20°C it has a solubility of 0.2 mg/mL in methanol, 1.3 mg/mL in propylene glycol, and 1.7 mg/mL in water. In aqueous buffer (pH 2) the solubility is 10.0 mg/mL. Penciclovir is not hygroscopic. Its partition coefficient in n-octanol/water at pH 7.5 is 0.024 (logP = -1.62).
Before taking penciclovir, tell your doctor:
- If you are allergic to penciclovir; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
This medicine may interact with other drugs or health problems.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take penciclovir with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take penciclovir?
- Tell all of your health care providers that you take penciclovir. This includes your doctors, nurses, pharmacists, and dentists.
- This medicine will not cure cold sores. If you have questions, talk with the doctor.
- Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using penciclovir while you are pregnant.
- Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.
How is penciclovir best taken?
Use penciclovir as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- Use at the first sign of a cold sore.
- Do not take penciclovir by mouth. Use on your lips and face only. Keep out of your mouth, nose, and eyes (may burn).
- Wash your hands before and after use.
- Clean affected part before use. Make sure to dry well.
- Put a thin layer on the affected skin and rub in gently.
- Do not use penciclovir for longer than you were told by your doctor.
What do I do if I miss a dose?
- Use a missed dose as soon as you think about it.
- If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
- Do not use 2 doses at the same time or extra doses.
What are the side effects of penciclovir that I need to call my doctor about immediately?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Very bad irritation where penciclovir is used.
What are some other side effects of penciclovir?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Irritation where penciclovir is used.
- Change in taste.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
If overdose is suspected:
If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
How do I store and/or throw out penciclovir?
- Store at room temperature.
- Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
- Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
PRINCIPAL DISPLAY PANEL – 1%
- NDC 0378-9720-55
(penciclovir cream) 1%
For Topical Use Only
- 5 g (Net Wt.)
- Each gram contains 10 mg penciclovir; inactive ingredients consist of cetomacrogol 1000
BP, cetostearyl alcohol, mineral oil, propylene glycol, purified water and white petrolatum.
- Usual Dosage: See accompanying prescribing information.
- To Open Tube: Unscrew cap, puncture aluminum seal with pointed end of cap.
- Store at controlled room temperature 20° to 25°C (68° to 77°F).
[See USP Controlled Room Temperature.]
- Denavir® is a registered trademark of Denco Asset, LLC, a Mylan Company
© 2018 Mylan Pharmaceuticals Inc.
- Comments or Questions? Call 1-877-446-3679 (1-877-4-INFO-RX)
- Manufactured in Canada for:
Mylan Pharmaceuticals Inc.
Morgantown, WV 26505 U.S.A.
SRC: NLM .