Comprehensive medication guide to Zovirax including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$20 copay for generic acyclovir on most insurance plans; covered as Tier 1 (preferred generic) on the majority of formularies. Medicare Part D covers generic acyclovir with standard Tier 1 copays. Brand Zovirax may require prior authorization.
Estimated Cash Pricing
$15–$105 retail for generic acyclovir (varies by formulation and pharmacy); as low as $8–$15 with GoodRx or SingleCare coupons for a 60-tablet supply of acyclovir 400 mg. Brand Zovirax cream can exceed $400 without insurance.
Medfinder Findability Score
68/100
On this page
Zovirax is the brand name for acyclovir, a prescription antiviral medication first approved by the FDA in 1982. It belongs to the nucleoside analogue antiviral drug class and works by blocking herpes virus DNA replication. Acyclovir is one of the most widely prescribed antivirals in the world and is available in multiple forms: oral capsules, tablets, suspension, topical cream, topical ointment, and intravenous injection.
Zovirax treats infections caused by herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) and varicella-zoster virus (VZV). FDA-approved indications include genital herpes (initial and recurrent episodes, and chronic suppressive therapy), herpes zoster (shingles), varicella (chickenpox), and herpes labialis (cold sores) via topical cream. The IV form is used in hospitals for severe infections including HSV encephalitis and neonatal herpes.
Importantly, acyclovir does not cure herpes infections. The virus remains dormant in nerve cells even after treatment. However, acyclovir significantly reduces outbreak severity, duration, and frequency — and daily suppressive therapy reduces the risk of transmitting herpes to sexual partners.
We have a 99% success rate finding medications, even during nationwide shortages.
Need this medication?
Acyclovir's mechanism of action is elegantly selective. It requires viral thymidine kinase (TK) — an enzyme produced by herpes viruses — to convert it into its active form (acyclovir monophosphate). This first activation step is highly specific to HSV- and VZV-infected cells, meaning acyclovir is selectively activated where it's needed most and largely inactive in healthy, uninfected cells.
Once activated (converted to acyclovir triphosphate), the drug disrupts viral replication in three ways: it competitively inhibits viral DNA polymerase, gets incorporated into and terminates the growing viral DNA chain, and inactivates viral DNA polymerase. This triple mechanism effectively halts the virus's ability to copy itself.
Because acyclovir only works on actively replicating virus, timing matters. For shingles, starting within 72 hours of rash onset is critical. For genital herpes outbreaks, starting at the very first sign (tingling, burning) gives the best results. Daily suppressive therapy works by intercepting viral replication before it causes symptoms.
200 mg — capsule
Used for genital herpes treatment and some suppressive therapy regimens
400 mg — tablet
Most common dose; used for suppressive therapy (400 mg BID) and episodic treatment
800 mg — tablet
Used for shingles (800 mg 5x/day) and chickenpox in adults
200 mg/5 mL — oral suspension
Banana-flavored liquid form; used for children and patients who cannot swallow tablets
5% (50 mg/g) — topical cream
For recurrent herpes labialis (cold sores) in adults and adolescents 12+; applied 5 times daily for 4 days
5% (50 mg/g) — topical ointment
For mucocutaneous HSV in immunocompromised patients; not as effective as oral antivirals for most indications
50 mg/mL — IV injection
Hospital use only for HSV encephalitis, neonatal herpes, and severe VZV in immunocompromised patients
Oral acyclovir (tablets, capsules, and suspension) is generally available at most pharmacies in 2026, but individual locations can and do run out temporarily due to uneven distribution and demand spikes. The injectable (IV) form has experienced intermittent shortages since 2020 and continues to face supply fluctuations, with at least one supplier reporting backorder status as of April 2026.
The supply situation for oral acyclovir is described as stable but fragile. Spot shortages at individual pharmacies tend to resolve within days to a few weeks. Rural and underserved pharmacies face greater access challenges. Generic manufacturer consolidation means a single production disruption can destabilize supply rapidly.
If your pharmacy is out of acyclovir, medfinder can call pharmacies near you to find which ones have it in stock and text you the results.
Zovirax (acyclovir) is not a controlled substance, which means any licensed prescriber can write a prescription without special DEA authorization or additional prescribing restrictions. This makes acyclovir one of the most accessible prescription antivirals — obtainable from a wide range of healthcare providers, including telehealth platforms.
Providers who commonly prescribe acyclovir include:
Primary care physicians (family medicine, internal medicine)
Nurse practitioners (NPs) and physician assistants (PAs)
OB/GYNs (for genital herpes, including pregnancy management)
Dermatologists (for herpes labialis, shingles rash, topical prescriptions)
Infectious disease specialists (for complex or severe HSV/VZV cases)
Pediatricians (for chickenpox, pediatric herpes infections)
Ophthalmologists (for herpes keratitis/eye infections)
Telehealth platforms such as Teladoc, MDLive, Wisp, and Nurx can diagnose herpes infections and prescribe acyclovir or valacyclovir in a single virtual visit — often the same day. This is particularly convenient for patients experiencing an active outbreak who need medication quickly.
No. Zovirax (acyclovir) is not a controlled substance and is not scheduled by the DEA. It is a prescription-only medication, but it has no abuse potential and does not fall under any federal controlled substance scheduling.
Because acyclovir is not a controlled substance, prescribers face no special restrictions on issuing prescriptions. Patients can receive 90-day supplies, obtain refills by phone or patient portal, and use telehealth services without additional hurdles. Pharmacies can also transfer prescriptions between locations freely.
Oral acyclovir is generally well tolerated. The most common side effects include:
Headache (most common)
Nausea (about 4.8% with long-term use)
Vomiting
Diarrhea (about 2.4% with long-term use)
Malaise (general feeling of being unwell)
Serious side effects requiring immediate medical attention:
Acute renal failure (kidney damage) — maintain adequate hydration, drink 6–8 glasses of water daily
CNS effects: confusion, hallucinations, somnolence, tremors (more common in elderly or those with kidney impairment)
Severe cutaneous reactions: Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), DRESS, AGEP — stop drug immediately and seek emergency care
TTP/HUS (rare, primarily in immunocompromised patients)
Severe allergic reactions: hives, difficulty breathing, swelling of face/lips/tongue/throat
Know what you need? Skip the search.
Valacyclovir (Valtrex)
Prodrug of acyclovir with 3–5x higher oral bioavailability; requires less frequent dosing (once daily for suppression vs. twice daily); equivalent efficacy for all outpatient HSV/VZV indications; widely available as generic; typically $10–$25 with discount cards
Famciclovir (Famvir)
Prodrug of penciclovir; FDA-approved for genital herpes, shingles, and cold sores; less frequent dosing than acyclovir; available as generic; typically $15–$40 with discount cards
Penciclovir (Denavir)
Topical antiviral cream for cold sores; applied every 2 hours while awake for 4 days; prescription required; an alternative to topical Zovirax cream
Foscarnet
IV antiviral for acyclovir-resistant HSV; not used as a routine first-line alternative; significant nephrotoxicity risk requires close monitoring; used only when acyclovir and valacyclovir have failed
Prefer Zovirax? We can find it.
Probenecid
moderateBlocks acyclovir kidney elimination, increasing acyclovir blood levels. May increase efficacy and toxicity risk. Monitor for increased side effects.
Cimetidine
moderateCompetes with acyclovir for kidney elimination, potentially increasing acyclovir levels. Usually not clinically significant at OTC doses.
Mycophenolate mofetil (CellCept)
moderateMutual increase in blood levels of both drugs via competing kidney elimination. Important in transplant patients who take both drugs. Monitor for increased side effects from both.
Amphotericin B
majorBoth drugs are nephrotoxic; combined use significantly increases kidney damage risk. Avoid combination when possible.
Cidofovir
majorBoth drugs are nephrotoxic; combined use significantly increases kidney damage risk. Avoid combination.
Cyclosporine
moderateBoth drugs can cause kidney damage. Combined use increases nephrotoxicity risk; close kidney function monitoring required, especially in transplant patients.
Tacrolimus
moderateBoth drugs can cause kidney damage. Close monitoring of kidney function required when used together.
Tenofovir
moderateBoth drugs have nephrotoxic potential. Combined use (common in HIV patients) increases kidney damage risk. Monitor kidney function closely.
Talimogene laherparepvec (T-VEC)
majorAcyclovir may reduce the effectiveness of this oncolytic virus therapy by interfering with its herpes virus-based mechanism. Do not use together.
Zovirax (acyclovir) has been a cornerstone of herpes antiviral therapy for over 40 years, and its combination of proven efficacy, broad applicability, and low cost (as a generic) makes it one of the most important medications on the market. For most patients on oral acyclovir, supply challenges are manageable with proactive refill planning and knowledge of alternatives.
The key principles for patients in 2026: always use generic acyclovir (never pay brand prices when the generic is identical), use discount cards like GoodRx or SingleCare to bring costs to $8–$15, refill your prescription 5–7 days before running out, and ask your doctor for a 90-day supply if you're on suppressive therapy.
If you ever can't find acyclovir at your pharmacy, medfinder is here to help — we call pharmacies near you to find which ones have your medication in stock and text you the results so you can get treatment without the runaround.
Medfinder Editorial Standards
Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
Real-time availability
Medfinder is actively checking pharmacy inventory for Zovirax. We don't publish a number until we have enough verified pharmacy checks to be accurate — start a search and our team confirms current availability near you, usually within 24 hours.
ChatGPT
Claude
Gemini