Herplex (Aciclovir)

Herplex is indicated for the topical management of skin infections caused by herpes simplex virus and herpes zoster virus, aiming to reduce lesion severity and accelerate healing.

• Cold sores (herpes labialis) on the lips or perioral skin.
• Genital herpes lesions on external genitalia.
• Shingles (herpes zoster) skin eruptions.
• Early treatment of recurrent herpes outbreaks to reduce symptom duration.
• Post‑exposure prophylaxis for minor skin abrasions after known exposure to HSV.
• Herpes simplex infections on the face, neck, or other non‑genital areas.
• Suppurative or ulcerated lesions where aciclovir can penetrate the epidermis.

• After topical application, aciclovir penetrates infected keratinocytes and is phosphorylated by viral thymidine kinase to aciclovir monophosphate, then by cellular kinases to the active triphosphate form. Aciclovir triphosphate competitively inhibits viral DNA polymerase and incorporates into viral DNA, causing chain termination and preventing further viral replication within the lesion. The selective activation in virus‑infected cells limits toxicity to surrounding healthy tissue.

Topical aciclovir is generally well tolerated, but local and systemic adverse reactions can occur.

Common

• Mild burning or stinging at the application site.
• Transient itching or redness.
• Dryness or peeling of the treated skin.
• Slight swelling or irritation.
• Minor crust formation as lesions heal.
• Temporary discoloration or hyperpigmentation of the skin.
• Localized swelling that resolves within a few hours.

Serious

• Allergic contact dermatitis with widespread rash.
• Severe skin ulceration or necrosis.
• Systemic hypersensitivity reactions such as fever or malaise.
• Rare ocular irritation if applied near the eye.
• Stevens-Johnson syndrome or toxic epidermal necrolysis (extremely rare).
• Systemic aciclovir toxicity manifesting as renal impairment in patients with extensive skin absorption.

When using Herplex, certain precautions help ensure safe and effective treatment and reduce the risk of adverse events.

• Avoid applying to mucous membranes, eyes, or open wounds unless directed by a healthcare professional.
• Do not use on extensive skin areas or broken skin without medical supervision.
• Discontinue use and seek medical advice if a rash or severe irritation develops.
• Store the product at room temperature, away from direct sunlight and moisture.
• Keep out of reach of children; accidental ingestion should be reported.
• Inform a physician of any known allergies to aciclovir or similar antivirals.
• Use the product only for the indicated viral infections; off‑label use may be ineffective.

Topical aciclovir may interact with other topical agents or systemic medications that affect skin integrity or viral replication.

Avoid

• Concurrent use of other antiviral creams containing penciclovir or idoxuridine on the same area.
• Application of corticosteroid ointments that may mask infection signs.
• Do not apply over large areas of compromised skin, as systemic absorption may increase.

Use with caution

• Systemic aciclovir or valacyclovir therapy, as combined antiviral effect may increase local drug concentration.
• Topical irritants such as benzoyl peroxide or salicylic acid, which could enhance skin irritation.
• Use with photosensitizing agents; excessive sun exposure may worsen skin reactions.
• Concurrent use with topical antibiotics may increase risk of contact dermatitis.