Herpex (Aciclovir)

Herpex is indicated for the topical treatment of viral infections caused by herpes viruses. It is commonly employed to manage lesions and reduce symptom duration.

• Cold sores (herpes labialis) caused by herpes simplex virus type 1
• Genital herpes outbreaks caused by herpes simplex virus type 2
• Herpes zoster (shingles) skin lesions
• Post‑herpetic erythema or crusting
• Prevention of viral spread to adjacent skin areas

• Aciclovir is taken up by infected cells and phosphorylated by viral thymidine kinase to aciclovir monophosphate, which is then converted to the active triphosphate form by cellular kinases. Aciclovir triphosphate competitively inhibits viral DNA polymerase and incorporates into viral DNA, causing premature chain termination and halting viral replication without affecting host DNA synthesis.

Adverse reactions to topical aciclovir are generally mild, but some users may experience more serious events.

Common

• Local skin irritation or burning sensation
• Redness or erythema at the application site
• Itching or pruritus
• Dryness or peeling of the treated skin
• Mild headache (rare)

Serious

• Allergic contact dermatitis with swelling or blistering
• Severe skin ulceration or necrosis
• Systemic hypersensitivity reactions such as urticaria or angioedema
• Rare systemic toxicity in patients with extensive skin involvement

Before using Herpex, consider the following safety points:

• Confirm that the lesion is caused by a herpes virus; avoid use on bacterial or fungal infections.
• Do not apply to damaged, inflamed, or broken skin beyond the target lesion.
• Use with caution in patients with known hypersensitivity to aciclovir or related compounds.
• Pregnant or breastfeeding individuals should consult a healthcare professional before use.
• Keep the product out of reach of children; accidental ingestion may require medical attention.
• Discontinue use and seek medical advice if severe irritation or allergic signs develop.

Topical aciclovir has limited systemic absorption, yet certain substances may affect its safety or efficacy.

Avoid

• Concurrent use of other topical antivirals on the same area, which may increase local irritation.
• Application of occlusive dressings that trap heat and moisture, enhancing absorption and risk of adverse effects.

Use with caution

• Systemic antiviral agents (e.g., oral aciclovir, valacyclovir) as combined therapy may increase overall drug exposure.
• Topical corticosteroids, which could mask signs of infection or alter healing.
• Dermatologic agents containing alcohol or strong irritants that may exacerbate skin reactions.