Package insert / product label
Dosage form: ointment
Drug class: Topical antivirals

Medically reviewed by Drugs.com. Last updated on Nov 1, 2021.

Acyclovir Ointment 5%

RX only

DESCRIPTION

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

Acyclovir is a white to off-white, crystalline powder with the molecular formula C8H11N5O3 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 2-amino-1,9-dihydro-9-[(2-hydroxyethoxy)methyl]-6H-purin-6-one; it has the following structural formula:

VIROLOGY

Mechanism of Antiviral Action: Acyclovir is a synthetic purine nucleoside analogue with in vitro and in vivo inhibitory activity against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella zoster virus (VZV).

The inhibitory activity of acyclovir is highly selective due to its affinity for the enzyme thymidine kinase (TK) encoded by HSV and VZV. This viral enzyme converts acyclovir into acyclovir monophosphate, a nucleotide analogue. The monophosphate is further converted into diphosphate by cellular guanylate kinase and into triphosphate by a number of cellular enzymes. In vitro, acyclovir triphosphate stops replication of herpes viral DNA. This is accomplished in 3 ways: 1) competitive inhibition of viral DNA polymerase, 2) incorporation into and termination of the growing viral DNA chain, and 3) inactivation of the viral DNA polymerase. The greater antiviral activity of acyclovir against HSV compared to VZV is due to its more efficient phosphorylation by the viral TK.

Antiviral Activities: The quantitative relationship between the in vitro susceptibility of herpes viruses to antivirals and the clinical response to therapy has not been established in humans, and virus sensitivity testing has not been standardized. Sensitivity testing results, expressed as the concentration of drug required to inhibit by 50% the growth of virus in cell culture (IC50 ), vary greatly depending upon a number of factors. Using plaque-reduction assays, the IC50 against HSV isolates ranges from 0.02 to 13.5 mcg/mL for HSV-1 and from 0.01 to 9.9 mcg/mL for HSV-2. The IC50 for acyclovir against most laboratory strains and clinical isolates of VZV ranges from 0.12 to 10.8 mcg/mL. Acyclovir also demonstrates activity against the Oka vaccine strain of VZV with a mean IC50 of 1.35 mcg/mL.

Drug Resistance: Resistance of HSV and VZV to acyclovir can result from qualitative and quantitative changes in the viral TK and/or DNA polymerase. Clinical isolates of HSV and VZV with reduced susceptibility to acyclovir have been recovered from immune compromised patients, especially with advanced HIV infection. While most of the acyclovir-resistant mutants isolated thus far from immune compromised patients have been found to be TK-deficient mutants, other mutants involving the viral TK gene (TK partial and TK altered) and DNA polymerase have been isolated. TK-negative mutants may cause severe disease in infants and immune compromised adults. The possibility of viral resistance to acyclovir should be considered in patients who show poor clinical response during therapy.

CLINICAL PHARMACOLOGY

Two clinical pharmacology studies were performed with Acyclovir Ointment 5% in immune compromised adults at risk of developing mucocutaneous HSV infections or with localized varicella-zoster infections. These studies were designed to evaluate the dermal tolerance, systemic toxicity, and percutaneous absorption of acyclovir.

In one 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 9 patients and in the urine of all patients tested. Acyclovir levels in plasma ranged from <0.01 to 0.28 mcg/mL in 8 patients with normal renal function, and from <0.01 to 0.78 mcg/mL in 1 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.

CLINICAL TRIALS

In clinical trials of initial genital herpes infections, Acyclovir Ointment 5% has shown a decrease in healing time and, in some cases, a decrease in duration of viral shedding and duration of pain. In studies in immune compromised patients primarily with herpes labialis, there was a decrease in duration of viral shedding and a slight decrease in duration of pain.

In studies of recurrent genital herpes and of herpes labialis in nonimmuno compromised patients, there was no evidence of clinical benefit; there was some decrease in duration of viral shedding.

INDICATIONS AND USAGE

Acyclovir Ointment 5% is indicated in the management of initial genital herpes and in limited nonlifethreatening mucocutaneous HSV infections in immune compromised patients.

CONTRAINDICATIONS

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

WARNINGS

Acyclovir Ointment 5% is intended for cutaneous use only and should not be used in the eye.

PRECAUTIONS

General: The recommended dosage, frequency of applications, and length of treatment should not be exceeded (see DOSAGE AND ADMINISTRATION). There are no data to support the use of Acyclovir Ointment 5% to prevent transmission of infection to other persons or prevent recurrent infections when applied in the absence of signs and symptoms. Acyclovir Ointment 5% should not be used for the prevention of recurrent HSV infections. Although clinically significant viral resistance associated with the use of Acyclovir Ointment 5% has not been observed, this possibility exists.

Drug Interactions: Clinical experience has identified no interactions resulting from topical or systemic administration of other drugs concomitantly with Acyclovir Ointment 5%.

Carcinogenesis, Mutagenesis, Impairment of Fertility: Systemic exposure following topical administration of acyclovir is minimal. Dermal carcinogenicity studies were not conducted. Results from the studies of carcinogenesis, mutagenesis, and fertility are not included in the full prescribing information for Acyclovir Ointment 5% due to the minimal exposures of acyclovir that result from dermal application. Information on these studies is available in the full prescribing information for acyclovir capsules, tablets, and oral suspension and acyclovir for injection.

Pregnancy: Teratogenic Effects: Acyclovir was not teratogenic in the mouse, rabbit, or rat at exposures greatly in excess of human exposure. There are no adequate and well-controlled studies of systemic acyclovir in pregnant women. A prospective epidemiologic registry of acyclovir use during pregnancy was established in 1984 and completed in April 1999. There were 749 pregnancies followed in women exposed to systemic acyclovir during the first trimester of pregnancy resulting in 756 outcomes. The occurrence rate of birth defects approximates that found in the general population. However, the small size of the registry is insufficient to evaluate the risk for less common defects or to permit reliable or definitive conclusions regarding the safety of acyclovir in pregnant women and their developing fetuses. Systemic acyclovir should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Nursing Mothers: It is not known whether topically applied acyclovir is excreted in breast milk. Systemic exposure following topical administration is minimal. After oral administration of acyclovir, acyclovir concentrations have been documented in breast milk in 2 women and ranged from 0.6 to 4.1 times the corresponding plasma levels. These concentrations would potentially expose the nursing infant to a dose of acyclovir up to 0.3 mg/kg/day. Nursing mothers who have active herpetic lesions near or on the breast should avoid nursing.

Geriatric Use: Clinical studies of Acyclovir Ointment did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. Systemic absorption of acyclovir after topical administration is minimal (see CLINICAL PHARMACOLOGY).

Pediatric Use: Safety and effectiveness in pediatric patients have not been established.

Adverse Reactions

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 2 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.

Observed During Clinical Practice: Based on clinical practice experience in patients treated with Acyclovir Ointment in the U.S., spontaneously reported adverse events are uncommon. Data are insufficient to support an estimate of their incidence or to establish causation. These events may also occur as part of the underlying disease process. Voluntary reports of adverse events that have been received since market introduction include:

General: Edema and/or pain at the application site.

Skin: Pruritus, rash.

To report SUSPECTED ADVERSE REACTIONS, contact Solco Healthcare US, LLC at 1-866-257-2597 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

OVERDOSAGE

Overdosage by topical application of Acyclovir Ointment 5% is unlikely because of limited transcutaneous absorption (see CLINICAL PHARMACOLOGY).

DOSAGE AND ADMINISTRATION

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.

HOW SUPPLIED

Each gram of Acyclovir Ointment, USP 5% contains 50 mg acyclovir, USP in a polyethylene glycol base. Acyclovir Ointment, USP 5% is a white to off white ointment, free of foreign matters, free of lumps, translucent, homogeneous, and no phase separation. It is supplied as follows:

15 g tubes NDC 43547-499-42

30 g tubes NDC 43547-499-41

Store at 15° to 25°C (59° to 77°F) in a dry place.

Manufactured by:

UBI Pharma Inc.

No. 45, Guangfu N. Rd., Hukou, Hsinchu 30351, Taiwan (TWN)

Distributed by:

Solco Healthcare US, LLC

Somerset, NJ 08873, USA

Rev.: 09/2019

L187-01

Package/Label Display Panel

Carton Label-15 g

Rx only

NDC 43547-499-42

Acyclovir Ointment, USP 5%

15 g

Each gram contains acyclovir, USP 50 mg in a polyethylene glycol base.

USUAL DOSAGE: Apply 6 times a day (every 3 hours) for 7 days.

See prescribing information for dosage information.

Store at 15°C to 25°C (59°F to 77°F) in a dry place.

Manufactured by:

UBI Pharma Inc.

No. 45, Guangfu N. Rd., Hukou, Hsinchu 303036, Taiwan (TWN)

Distributed by:

Solco Healthcare US, LLC

Somerset, NJ 08873, USA

Rev.: 09/2019

Package/Label Display Panel

Carton Label-30 g

Rx only

NDC 43547-499-41

Acyclovir Ointment, USP 5%

30 g

Each gram contains acyclovir, USP 50 mg in a polyethylene glycol base.

USUAL DOSAGE: Apply 6 times a day (every 3 hours) for 7 days.

See prescribing information for dosage information.

Store at 15°C to 25°C (59°F to 77°F) in a dry place.

Manufactured by:

UBI Pharma Inc.

No. 45, Guangfu N. Rd., Hukou, Hsinchu 303036, Taiwan (TWN)

Distributed by:

Solco Healthcare US, LLC

Somerset, NJ 08873, USA

Rev.: 09/2019

Medical Disclaimer

Medically reviewed by Drugs.com. Last updated on Nov 2, 2022.

Commonly used brand name(s)

In the U.S.

• Avaclyr

Pharmacologic Class: Viral DNA Polymerase Inhibitor

Chemical Class: Guanosine Nucleoside Analog

Uses for acyclovir

Acyclovir ophthalmic ointment is used to treat acute herpetic keratitis (dendritic ulcers) in patients with herpes simplex (HSV-1 and HSV-2) virus.

Acyclovir is available only with your doctor''s prescription.

Before using acyclovir

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For acyclovir, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to acyclovir or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of acyclovir ophthalmic ointment in children younger than 2 years of age. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of acyclovir ophthalmic ointment in the elderly.

Breastfeeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Interactions with medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Interactions with food/tobacco/alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Proper use of acyclovir

Use acyclovir only as directed by your doctor. Do not use more of it, do not use it more often, and do not use it for a longer time than your doctor ordered.

To use the eye ointment:

• Wash your hands with soap and water before and after you use acyclovir.
• Tilt the head back. Press your finger gently on the skin just beneath the lower eyelid and pull the lower eyelid away from the eye to make a pocket.
• Squeeze a ribbon of ointment into the pocket between your lower lid and eyeball. Close your eyes for 1 to 2 minutes. You may wipe the excess ointment away.
• Wipe the tip with a clean tissue and close the tube tightly. Keep the tube tightly closed when you are not using it.
• To keep the medicine as germ-free as possible, do not touch the applicator tip to any surface (including the eye). Also, keep the container tightly closed. Serious damage to the eye and possible loss of vision may result from using contaminated eye medicines.

Dosing

The dose of acyclovir will be different for different patients. Follow your doctor''s orders or the directions on the label. The following information includes only the average doses of acyclovir. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For ophthalmic solution dosage form (eye ointment):
  • For acute herpetic keratitis:
    • Adults and children 2 years of age and older—Apply a 1 centimeter (cm) ribbon of ointment in the affected eye 5 times per day (about every 3 hours while awake) until the eye heals, and then a 1 cm ribbon 3 times per day for 7 days.
    • Children younger than 2 years of age—Use and dose must be determined by your doctor.

Missed dose

If you miss a dose of acyclovir, apply it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using acyclovir

It is very important that your eye doctor (ophthalmologist) check your progress at regular visits to make sure acyclovir is working properly and to check for unwanted effects.

If eye pain or irritation occurs, or symptoms do not improve within a few days or if they become worse, check with your doctor right away.

Acyclovir side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

• Eye pain or sting
• painful irritation of the clear front part of the eye
• redness, itching, pain, swelling, or other irritation of the eye

Rare

• Redness, swelling, or itching of the eyelid

Incidence not known

• Hives or welts, itching, skin rash
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
• redness of the skin

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer