Acyclovir
Also sold as Acyclovir, acyclovir, ACYCLOVIR, Zovirax
From 12 official FDA drug labels · RxNorm 141859
What it is used for
These are the uses the FDA has approved for this label. Using it for anything else is “off-label”: ask your prescriber why.
1 INDICATIONS AND USAGE Acyclovir Cream is a herpes simplex virus (HSV) deoxynucleoside analogue DNA polymerase inhibitor indicated for the treatment of recurrent herpes labialis (cold sores) in immunocompetent adults and adolescents 12 years of age and older. Acyclovir Cream is a herpes simplex virus (HSV) deoxynucleoside analogue DNA polymerase inhibitor indicated for the treatment of recurrent herpes labialis (cold sores) in immunocompetent adults and adolescents 12 years of age and older. ( 1 )
How to take it
2 DOSAGE AND ADMINISTRATION Acyclovir Cream should be applied 5 times per day for 4 days. Therapy should be initiated as early as possible following the onset of signs or symptoms of herpes labialis, i.e. during the prodrome or when lesions appear. For adolescents 12 years of age and older, the dosage is the same as in adults. Apply 5 times a day for 4 days. ( 2 ) Administer immediately following the onset of cold sore lesions. ( 2 )
Do not take it if
4 CONTRAINDICATIONS Acyclovir Cream is contraindicated in patients with known hypersensitivity to acyclovir, valacyclovir, or any component of the formulation. Acyclovir Cream is contraindicated in patients with known hypersensitivity to acyclovir, valacyclovir or any component of the formulation. ( 4 )
Serious warnings and precautions
5 WARNINGS AND PRECAUTIONS Only for topical use of recurrent HSV lesions on the external aspect of lips and the face. Acyclovir Cream should not be applied on mucous membranes including in the eye or inside the mouth or nose. ( 5.1 ) There is a potential for irritation and contact sensitization. ( 5.2 ) 5.1 General Acyclovir Cream should only be applied on the affected external aspects of the lips and face in patients with herpes labialis. Because no data are available, application to human mucous membranes is not recommended. Acyclovir Cream is intended for cutaneous use only and should not be used in the eye or inside the mouth or nose. 5.2 Contact Sensitization Acyclovir Cream has a potential for irritation and contact sensitization [see Adverse Reactions (6.1) ] . The effect of Acyclovir Cream has not been established in immunocompromised patients.
Common side effects
From the label’s clinical-trial and reporting data. Serious problems are under the warnings above.
6 ADVERSE REACTIONS The most common adverse reactions reported were local skin reactions at the application site. ( 6.1 ) Angioedema, anaphylaxis, contact dermatitis and eczema have been reported. ( 6.2 ) To report SUSPECTED ADVERSE REACTIONS, contact Bausch Health US, LLC at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug, and may not reflect the rates observed in clinical practice. In five double-blind, placebo-controlled trials, 1124 patients were treated with Acyclovir Cream and 1161 with placebo (vehicle) cream. Local application site reactions were reported by 5% of patients receiving Acyclovir Cream and 4% of patients receiving placebo. The most common adverse reactions at the site of topical application were dry lips, desquamation, dryness of skin, cracked lips, burning skin, pruritus, flakiness of skin, and stinging on skin; each adverse reaction occurred in less than 1% of patients receiving Acyclovir Cream and placebo. Three patients on Acyclovir Cream and one patient on placebo discontinued treatment due to an adverse event. An additional study, enrolling 22 healthy adults, was conducted to evaluate the dermal tolerance of Acyclovir Cream compared with vehicle using single occluded and semi-occluded patch testing methodology. Both Acyclovir Cream and placebo showed a high and cumulative irritation potential. Another study, enrolling 251 healthy adults, was conducted to evaluate the contact sensitization potential of Acyclovir Cream using repeat insult patch testing methodology. Of 202 evaluable subjects, possible cutaneous sensitization reactions were observed in the same 4 (2%) subjects with both Acyclovir Cream and placebo, and these reactions to both Acyclovir Cream and placebo were confirmed in 3 subjects upon rechallenge. The sensitizing ingredient(s) has not been identified. The safety profile in patients 12 to 17 years of age was similar to that observed in adults. 6.2 Postmarketing Experience In addition to adverse events reported from clinical trials, the following events have been identified during postapproval use of acyclovir cream. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to a combination of their seriousness, frequency of reporting, or potential causal connection to acyclovir cream. General: Angioedema, anaphylaxis. Skin: Contact dermatitis, eczema.
Taking it with other medicines
7 DRUG INTERACTIONS Clinical experience has identified no interactions resulting from topical or systemic administration of other drugs concomitantly with Acyclovir Cream. Due to minimal systemic absorption of Acyclovir Cream, systemic drug interactions are unlikely. Clinical experience has identified no interactions resulting from topical or systemic administration of other drugs concomitantly with Acyclovir Cream. Due to minimal systemic absorption of Acyclovir Cream, systemic drug interactions are unlikely. ( 7 )
If you are pregnant or breastfeeding
8.1 Pregnancy Risk Summary Acyclovir is minimally absorbed systemically following topical route of administration, and maternal use is not expected to result in fetal exposure to the Acyclovir Cream [see Clinical Pharmacology (12.3) ] . Experience with topical acyclovir use in pregnant women over several decades, based on published literature including observational studies, has not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Animal reproduction studies with systemic exposure of acyclovir have been conducted. Refer to acyclovir prescribing information for additional details. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
If you take too much
10 OVERDOSAGE Overdosage by topical application of Acyclovir Cream is unlikely because of minimal systemic exposure [see Clinical Pharmacology (12.3) ] . There is no information available for overdose.
Forms and strengths available
From RxNorm. Which forms and strengths are actually stocked varies by pharmacy and country.
Reactions people have reported
These are counts from 15 voluntary reports to the FDA. They show what has been reported — they are not how common a side effect is, and they do not prove the medicine caused it.
Recalls
Research & studies
Recent higher-quality studies about Acyclovir, from PubMed. We link to the source — titles only. This is not medical advice.
Similar medicines
Acyclovir belongs to the Nucleosides and nucleotides excl. reverse transcriptase inhibitors class. Other medicines in it:
Questions to ask your doctor or pharmacist
- Is this the right medicine for my condition, and how long should I take it?
- What side effects should I watch for, and which ones need urgent attention?
- Does this interact with my other medicines, supplements, or alcohol?
- What should I do if I miss a dose or take too much?
Why you can trust this
Everything above comes from official FDA drug labels (openFDA), not written by us. Here are the exact labels used.
- FDA labelBryant Ranch Prepack· version 7· published Sep 5, 2024· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelBryant Ranch Prepack· version 1· published May 29, 2025· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelCamber Pharmaceuticals, Inc.· version 4· published Feb 2, 2026· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelREMEDYREPACK INC.· version 7· published Apr 27, 2026· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelGolden State Medical Supply, Inc.· version 3· published Sep 30, 2024· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelHeritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc.· version 6· published Jul 24, 2026· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelBryant Ranch Prepack· version 8· published May 21, 2026· retrieved Oct 19, 2026· View this label on DailyMed
- FDA labelTeva Pharmaceuticals USA, Inc.· version 7· published Oct 23, 2025· retrieved Oct 19, 2026· View this label on DailyMed