ValacyclovirValacyclovir Hydrochloride

About Valacyclovir

The body converts valacyclovir to acyclovir, which stops herpes simplex and varicella-zoster viruses from copying their DNA; it does not cure herpes. In adults, the label covers cold sores (2 g twice, 12 hours apart, for one day, started at the earliest symptom), a first episode of genital herpes (1 g twice a day for 10 days), recurrent episodes (500 mg twice a day for 3 days, started at the first sign), daily suppression (1 g once a day, or 500 mg once a day with 9 or fewer recurrences a year; 500 mg twice a day in adults with HIV-1 and a CD4 count of at least 100), reducing transmission (500 mg once a day for an infected partner with 9 or fewer recurrences a year) and shingles (1 g three times a day for 7 days, most effective within 48 hours of the rash). Children can take it for cold sores from age 12 and, with normal immune function, for chickenpox from 2 to less than 18: 20 mg/kg three times a day for 5 days, up to 1 g a dose, started within 24 hours of the rash.

There is no boxed warning. Valacyclovir must not be taken after a clinically significant hypersensitivity reaction, such as anaphylaxis or a severe skin reaction, to valacyclovir, acyclovir or an ingredient. Acute kidney failure has been reported in older adults, in people with kidney disease given too high a dose, with other drugs that can harm the kidneys and without enough fluid. Agitation, hallucinations, confusion, delirium, seizures and encephalopathy have been reported in adults and children with or without reduced kidney function and in people with kidney disease given too high a dose; older adults are more likely to have them, and valacyclovir is stopped if they occur. Thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, serious blood disorders, sometimes fatal, occurred in trials in people with advanced HIV disease and in transplant recipients taking 8 g a day. Since November 2025 the contraindication and a new warning cover severe skin reactions, including AGEP, DRESS, Stevens-Johnson syndrome and toxic epidermal necrolysis: a painful rash involving mucous membranes, or a spreading severe rash, means stopping it at once. Headache, nausea and abdominal pain are the most common side effects in adults; headache in children.

Doses are lowered or spaced out for reduced kidney function, with a dose after each hemodialysis session. The label says genital herpes is frequently passed on without symptoms and advises safer sex practices with suppressive therapy; reduced transmission has not been shown beyond 8 months, with multiple partners or in non-heterosexual couples. For a child who cannot take tablets, the label describes how a pharmacist can make a 25 or 50 mg per mL suspension from 500 mg Valtrex tablets. Clinical data over several decades have not identified a risk of major birth defects, and acyclovir passes into breast milk.

Taking Valacyclovir

How to take it

With or without food, starting as soon as possible after symptoms begin. Take the two cold sore doses about 12 hours apart and stop after one day. Drink enough fluids, and keep taking a course even if you feel better.

If you miss a dose

Take it as soon as you remember. If it is almost time for the next dose, skip the missed dose and take the next one at the usual time. Do not take a double dose.

Storage

Tablets at 59 to 77 degrees F in a tightly closed container, out of reach of children; a suspension made by the pharmacist goes in the refrigerator and is thrown away after 28 days.

Interactions to know about

The label lists no clinically significant drug or food interactions, but kidney failure has been reported with other drugs that can harm the kidneys, so tell the prescriber about them and about kidney disease.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Valacyclovir differs from pharmacy to pharmacy

Generic valacyclovir is rated equivalent to Valtrex, so a prescription allowing a generic can be filled with any maker’s tablets, and quotes differ by each pharmacy’s fee and markup and by whether valacyclovir is on its flat-price generic list. A prescription that names Valtrex and blocks substitution is filled with the brand.

The quantity depends on the use, from two doses in one day for a cold sore to 10 days for a first genital herpes episode or a continuing supply for suppression, so each prescription is quoted as written. A suspension the pharmacist makes for a child includes that preparation in its quote.

Ways to pay less for Valacyclovir without insurance

• Check that the prescription allows a generic, unless the prescriber has a reason to require Valtrex.
• For daily suppression, ask the prescriber whether a ninety-day supply suits you once the dose is settled.
• Ask whether valacyclovir is on the pharmacy’s flat-price generic list, and compare more than one pharmacy.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Valacyclovir

1. 1.Is my dose right for my kidney function?
2. 2.How soon after symptoms start should I take my first dose?
3. 3.Which side effects, such as confusion or a painful rash, mean I should stop and call?
4. 4.Can I still pass genital herpes to my partner while I take it?

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