Acyclovir — uses, dosing, side effects & the brands that sell it · pharmaranks
Acyclovir: uses, dosing, side effects & brands
Acyclovir is a herpes simplex virus nucleoside analog dna polymerase inhibitor sold in the U.S. under 6 brand and generic names, for chickenpox, herpes genitalis and herpes labialis. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
By the pharmaranks editorial team·Reviewed against the FDA (openFDA label, NDC Directory & Enforcement) sources·How we research
Key facts
Drug class
Herpes Simplex Virus Nucleoside Analog Dna Polymerase Inhibitor
6 products — Zovirax, Acyclovir Sodium and Acyclovir, and others
Prescription?
Prescription only
Generic available?
Yes
Typical price
about $5 for a 30-count supply
How acyclovir is dosed
From the FDA label for Zovirax (application NDA018603). Other acyclovir products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
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 ZOVIRAX 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 side effects
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. Observed During Clinical Practice: Based on clinical practice experience in patients treated with ZOVIRAX 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 Bausch Health US, LLC at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Who shouldn’t take acyclovir
Ointment 5% is contraindicated in patients who develop hypersensitivity to the components of the formulation.
Acyclovir drug interactions
Clinical experience has identified no interactions resulting from topical or systemic administration of other drugs concomitantly with ZOVIRAX Ointment 5%.
Every acyclovir product we track (6)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
ZOVIRAX is the brand name for acyclovir, a synthetic nucleoside analogue active against herpes viruses. ZOVIRAX Ointment 5% is a formulation for topical administration. Each gram of ZOVIRAX Ointment 5% contains 50 mg of acyclovir in a polyethylene glycol (PEG) base. Acyclovir 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 225.20. 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]-6 H -purin-6-one; it has the following structural formula: Chemical Structure
What kind of drug is acyclovir?
The FDA classifies acyclovir as a herpes simplex virus nucleoside analog dna polymerase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take acyclovir with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run acyclovir against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is acyclovir sold under?
We track 6 acyclovir-containing products in the U.S.: Zovirax, Acyclovir Sodium, Acyclovir, Acyclovir in Sodium Chloride 0.9% Preservative Free, Avaclyr and Sitavig. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does acyclovir come in?
Across the brands we track, acyclovir is currently marketed as topical, injectable, capsule, solution, suspension and tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Yes. Our catalog lists 3 generic acyclovir products alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Has acyclovir been recalled?
The FDA's Enforcement database lists 2 recall records whose product description mentions acyclovir. The most recent: acyclovir sodium (Feb 5, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.