Herpzyl (Aciclovir)

Herpzyl is indicated for the topical treatment of several herpes‑virus skin conditions.

• Herpes labialis (cold sores) on the lips, perioral area, and adjacent facial skin.
• External genital herpes lesions, including ulcerative or vesicular eruptions on the penis, vulva, or perianal region.
• Herpes zoster (shingles) skin eruptions, particularly when lesions are localized and accessible for topical therapy.
• Early treatment of suspected HSV exposure on minor skin abrasions or cuts to potentially limit viral replication.
• Adjunctive therapy for recurrent oral or genital herpes, used under the guidance of a healthcare professional.

• Aciclovir, the antiviral component of Herpzyl, is a nucleoside analogue that is selectively taken up by infected cells and phosphorylated by the viral thymidine kinase. The monophosphate is then converted by cellular enzymes to aciclovir triphosphate, which competitively inhibits viral DNA polymerase and terminates DNA chain elongation, thereby preventing replication of herpes simplex and varicella‑zoster viruses. The selective activation limits toxicity to uninfected cells.

Topical aciclovir may cause local skin reactions, most of which are mild and reversible.

Common

• Mild burning or stinging sensation at the application site, usually lasting a few minutes.
• Slight itching or redness of the skin where the product is applied.
• Dryness or peeling of the treated area, which may be accompanied by flaking.
• Transient tingling sensation that resolves without intervention.
• Mild localized swelling that subsides within hours.

Serious

• Severe allergic dermatitis with marked swelling, blister formation, or extensive redness.
• Contact urticaria (hives) developing around the treated region, sometimes spreading to adjacent skin.
• Persistent irritation or ulceration that does not improve with continued use.
• Erythema multiforme‑like skin eruption presenting as target lesions.
• Rare systemic allergic reaction such as anaphylaxis, requiring immediate medical attention.

When using Herpzyl, certain precautions should be observed to ensure safe and effective application.

• Apply only to intact, unbroken skin; avoid use on mucous membranes or open wounds.
• Do not use if you have a known hypersensitivity to aciclovir or any formulation components.
• Keep the product out of reach of children; accidental ingestion may cause systemic effects.
• Wash hands before and after application to prevent spread to other body areas.
• Discontinue use and seek medical advice if a rash, swelling, or severe irritation develops.
• Avoid concurrent use of other topical antiviral agents unless directed by a healthcare professional.

Topical aciclovir generally has limited systemic interactions, but certain combinations may affect safety or efficacy.

Avoid

• Concurrent use of other topical antiviral preparations on the same area, which may increase local irritation.
• Application over skin treated with chemical peels or abrasive agents, risking enhanced absorption and irritation.
• Use together with topical corticosteroids unless prescribed, as steroids may suppress local immune response.

Use with caution

• Combining with other skin irritants such as retinoids or benzoyl peroxide; monitor for increased redness or peeling.
• Applying over areas where systemic antiviral therapy (oral aciclovir) is being taken; assess for cumulative antiviral effect.
• Use with caution in patients using immunosuppressive topical agents; monitor healing.