Acyclovir (Topical)

Prescribing Information (Research Brand)

Indications

Acyclovir cream are indicated for the treatment of herpes simplex virus infections of the skin including initial and recurrent genital herpes and herpes labialis.

Therapeutic Class

Topical Antiviral preparations

Pharmacology

Acyclovir exerts its antiviral effect on herpes simplex viruses (HSV) and varicella-zoster virus by interfering with DNA synthesis and inhibiting viral replication. The exact mechanisms of action against other susceptible viruses have not fully elucidated. In vitro studies with herpes simplex viruses indicate that acyclovir triphosphate is the pharmacologically active form of the drug; the triphosphate functions as both a substrate for and preferential inhibitor of viral DNA polymerase.

Dosage & Administration

Acyclovir cream should be applied to lesions or impending lesions 5 times daily (at 4 hourly intervals omitting the night-time dose). Treatment should continue for 5 days. If healing does not occur, treatment may be extended for up to 10 days.

Interaction

Concomitant administration of probenecid and acyclovir has reportedly increased the mean plasma half-life and decreased urinary excretion and renal clearance of acyclovir. Amphotericin B has been shown to potentiate the antiviral effect of acyclovir against pseudorabies virus in vitro when both drugs are added to the culture medium. Ketoconazole and acyclovir have shown dose-dependent, synergistic, antiviral activity against herpes simplex virus types 1 and 2 (HSV-1 and HSV -2) in in-vitro replication studies.

Contraindications

Acyclovir cream is contraindicated in patients known to be hypersensitive to acyclovir.

Side Effects

Skin rashes which, resolve after withdrawal of the drug have been reported with acyclovir. The most common adverse effect is mild pain including transient burning and stinging at the site of application following acyclovir cream.

Pregnancy & Lactation

Pregnancy Category-B. Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women OR Animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus in any trimester.

Precautions

Acyclovir cream is not recommended for application to mucous membrane such as eye, mouth, vagina etc.

Use in Special Population

HSV infections in children over 2 years should be given adult doses and children below 2 years should be given half of the adult dose.

Storage Conditions

Acyclovir cream should be stored below 25° C in a cool and dry place.