Get your patient on Acyclovir

Acyclovir ointment 5% is indicated in the management of initial genital herpes and in limited non-life threatening mucocutaneous Herpes simplex virus infections in immunocompromised patients.

Apply sufficient quantity to adequately cover all lesions every 3 hours, 6 times per day for 7 days. The dose size per application will vary depending upon the total lesion area but should approximate a one-half inch ribbon of ointment per 4 square inches of surface area. A finger cot or rubber glove should be used when applying acyclovir ointment to prevent autoinoculation of other body sites and transmission of infection to other persons. Therapy should be initiated as early as possible following onset of signs and symptoms.

Acyclovir ointment 5% is contraindicated in patients who develop hypersensitivity to the components of the formulation.

In the controlled clinical trials, mild pain (including transient burning and stinging) was reported by about 30% of patients in both the active and placebo arms; treatment was discontinued in two of these patients. Local pruritus occurred in 4% of these patients. In all studies, there was no significant difference between the drug and placebo group in the rate or type of reported adverse reactions nor were there any differences in abnormal clinical laboratory findings.

Clinical experience has identified no interactions resulting from topical or systemic administration of other drugs concomitantly with acyclovir ointment 5%.

Acyclovir Ointment, USP is a synthetic nucleoside analogue active against herpes viruses. Acyclovir Ointment 5% is a formulation for topical administration. Each gram of Acyclovir Ointment 5% contains 50 mg of acyclovir in a polyethylene glycol (PEG) base.

Acyclovir, USP is a white to off-white, crystalline powder with the molecular formula C ₈ H ₁₁ N ₅ O ₃ and a molecular weight of 225. The maximum solubility in water at 37°C is 2.5 mg/mL. The pka’s of acyclovir are 2.27 and 9.25. The chemical name of acyclovir is 9-[(2-Hydroxyethoxy) methyl]guanine; it has the following structural formula:

Two clinical pharmacology studies were performed with acyclovir ointment 5% in immunocompromised adults at risk of developing mucocutaneous herpes simplex virus infections or with localized varicella-zoster infections. These studies were designed to evaluate the dermal tolerance, systemic toxicity and percutaneous absorption of acyclovir.

In 1 of these studies, which included 16 inpatients, the complete ointment or its vehicle were randomly administered in a dose of 1 -cm strips (25 mg acyclovir) 4 times a day for 7 days to an intact skin surface area of 4.5 square inches. No local intolerance, systemic toxicity or contact dermatitis were observed. In addition, no drug was detected in blood and urine by radioimmunoassay (sensitivity, 0.01 mcg/mL).

The other study included 11 patients with localized varicella-zoster infections. In this uncontrolled study, acyclovir was detected in the blood of nine patients and in the urine of all patients tested. Acyclovir levels in plasma ranged from < 0.01 to 0.28 mcg/mL in eight patients with normal renal function, and from < 0.01 to 0.78 mcg/mL in one patient with impaired renal function. Acyclovir excreted in the urine ranged from < 0.02% to 9.4% of the daily dose. Therefore, systemic absorption of acyclovir after topical application is minimal.

Each gram of Acyclovir Ointment USP, 5% contains acyclovir USP, 50 mg in a polyethylene glycol base. Acyclovir Ointment USP, 5% is an opaque white to off-white ointment available as follows:

Store at 20° to 25°C (68° to 77°F). [See USP Controlled Room Temperature.]

Store in a dry place.