Nurses Compass
Drug Guide
Penciclovir
Classification
Therapeutic: Antiviral
Pharmacological: Nucleoside analog
FDA Approved Indications
- Herpes labialis (cold sores)
Mechanism of Action
Penciclovir inhibits viral DNA synthesis by acting as a substrate for viral DNA polymerase, leading to chain termination.
Dosage and Administration
Adult: Apply a thin layer to the affected area every 2 hours while awake for 4 days.
Pediatric: Safety and efficacy not established in pediatric patients.
Geriatric: No specific dosage adjustments; monitor for reactions.
Renal Impairment: No specific adjustments recommended; use with caution.
Hepatic Impairment: No data available.
Pharmacokinetics
Absorption: Minimal systemic absorption when applied topically.
Distribution: Limited due to minimal systemic absorption.
Metabolism: Not extensively metabolized.
Excretion: Primarily excreted unchanged in urine.
Half Life: Approximately 2 hours.
Contraindications
- Hypersensitivity to penciclovir or any component of the formulation.
Precautions
- Use with caution in patients with immunosuppression or extensive herpes outbreaks. Avoid contact with eyes. Explore potential for resistance.
Adverse Reactions - Common
- Application site reactions such as redness, itching, or burning. (Common)
Adverse Reactions - Serious
- Allergic reactions, including rash, swelling, or difficulty breathing. (Rare)
Drug-Drug Interactions
- None well documented
Drug-Food Interactions
- None
Drug-Herb Interactions
- Limited data available
Nursing Implications
Assessment: Assess lesion location, size, and severity before and during treatment.
Diagnoses:
- Ineffective tissue perfusion related to skin lesion.
- Risk for infection.
Implementation: Instruct patient to apply medication as prescribed, wash hands before and after application, and avoid touching or squeezing lesions.
Evaluation: Monitor for resolution of lesions and adverse reactions.
Patient/Family Teaching
- Apply medication as directed, typically 4 times daily for 4 days.
- Use separate applicator or finger cot to minimize spread.
- Wash hands before and after application.
- Avoid touching or picking at lesions.
Special Considerations
Black Box Warnings:
- None currently.
Genetic Factors: No known genetic factors affecting use.
Lab Test Interference: None noted.
Overdose Management
Signs/Symptoms: Local irritation or systemic symptoms are unlikely due to minimal absorption.
Treatment: Supportive care; no specific antidote.
Storage and Handling
Storage: Store at room temperature away from moisture and heat.
Stability: Stable until expiration date on packaging.