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Medically reviewed by Last updated on Sep 13, 2020.


(pen SYE kloe veer)

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Cream, External:

Denavir: 1% (5 g) [contains cetostearyl alcohol, propylene glycol]

Brand Names: U.S.

  • Denavir

Pharmacologic Category

  • Antiviral Agent


In cells infected with HSV-1 or HSV-2, viral thymidine kinase phosphorylates penciclovir to a monophosphate form which, in turn, is converted to penciclovir triphosphate by cellular kinases. Penciclovir triphosphate inhibits HSV polymerase competitively with deoxyguanosine triphosphate. Consequently, herpes viral DNA synthesis and, therefore, replication are selectively inhibited


Topical: None

Onset of Action

Resolution of pain: Adults: 3.5 days (Spruance 1997); Cutaneous healing: Adults: 4.8 days (Spruance 1997)

Use: Labeled Indications

Herpes labialis (cold sores): Topical treatment of recurrent herpes labialis (cold sores) adults and children ≥12 years of age


Hypersensitivity to the penciclovir or any component of the formulation

Dosing: Adult

Herpes labialis (cold sores): Topical: Apply cream at the first sign or symptom of cold sore (eg, tingling, swelling) or appearance of lesion; apply every 2 hours during waking hours for 4 days.

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Herpes labialis (cold sores): Children ≥12 years and Adolescents: Topical: Cream: Apply every 2 hours during waking hours for 4 days; start at the first sign or symptom of cold sore (eg, tingling, redness, itching, swelling) or appearance of lesion


Topical: Apply only to herpes labialis on the lips and face. Clean and dry affected area prior to application. Apply sufficient amount to cover lesions or area of tingling (or other symptoms) before the lesion appears; gently rub into the affected area. Avoid application in or near eyes since it may cause irritation. Wash hands with soap and water after application.


Store at controlled room temperature of 20°C to 25°C (68°F to 77°F).

Drug Interactions

Talimogene Laherparepvec: Antiherpetic Antivirals may diminish the therapeutic effect of Talimogene Laherparepvec. Monitor therapy

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

>10%: Dermatologic: Erythema (50%; mild)

1% to 10%:

Central nervous system: Headache (5%)

Local: Application site reaction (1%)

<1%, postmarketing, and/or case reports: Altered sense of smell, erythematous rash, local anesthesia, localized edema, oropharyngeal edema, pain, paresthesia, pruritus, skin discoloration, urticaria


Special populations:

• Immunocompromised patients: The effect of penciclovir has not been established in immunocompromised patients.

Other warnings/precautions:

• Appropriate use: Should only be used on herpes labialis on the lips and face; because no data are available, application to mucous membranes is not recommended. Avoid application in or near eyes since it may cause irritation.

Monitoring Parameters

Resolution of symptoms and healing of cold sore lesion

Pregnancy Considerations

Penciclovir is not absorbed systemically following topical administration; exposure to the fetus is not expected.

Patient Education

What is this drug used for?

• It is used to treat cold sores.

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:

• Change in taste

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:

• Severe skin irritation

• 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.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

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