Products
Lip creams containing aciclovir have been approved in many countries since 1997 (Zovirax Lip Cream, generic).
Structure and properties
Aciclovir (C8H11N5O3, Mr = 225.2 g/mol) exists as a white crystalline powder that is sparingly soluble in water. It mimics 2′-deoxyguanosine.
Effects
Aciclovir (ATC D06BB03) is antiviral against herpes simplex viruses. It is a prodrug that is converted to aciclovir triphosphate in virus-infected cells by viral thymidine kinase and subsequently by cellular kinases. Aciclovir triphosphate is used by viral polymerase as a false substrate in DNA synthesis. This leads to chain termination during nucleic acid formation.
Indications
For the treatment of cold sores of the lips and adjacent facial area.
Dosage
According to the professional information. The cream should be applied as early as possible at the first signs of cold sores. It is administered five times daily, every four hours. For hygienic reasons, hands should be washed well before and after administration. The usual duration of treatment is four days and can be extended to a maximum of ten days.
Contraindications
The cream is contraindicated in case of hypersensitivity. It should not be used on mucous membranes, the eye, or the genital tract. For complete precautions, see the drug label.
Interactions
Systemic drug interactions are not expected with topical use. Other cold sore creams should not be applied at the same time.
Adverse effects
Possible adverse effects include local reactions such as dry skin, redness, itching, burning, hypersensitivity reactions, and contact dermatitis.