What is Valtrex?

Valtrex is the brand name for valaciclovir, a prescription antiviral tablet used to treat and suppress genital herpes (HSV-1 and HSV-2) in adults.

It converts to aciclovir in the body, which stops the herpes virus from multiplying.

Although it does not cure herpes, Valtrex eases symptoms such as pain, itching and sores, speeds healing during outbreaks, and—when taken daily—reduces how often recurrences occur and lowers (but does not remove) the risk of passing the infection to a partner.

Valtrex can be taken with or without food.

What is Valtrex Used For?

Genital Herpes Treatment – shortens the length and severity of an outbreak and speeds healing.

Preventing Recurring Genital Herpes – daily suppressive therapy lowers the frequency of future episodes.

Lowering Transmission Risk – reduces, but does not eliminate, the chance of passing herpes to a partner when combined with safer-sex practices such as consistent condom use.


How Valtrex Works

Valtrex is converted in the body to aciclovir, which blocks the viral DNA polymerase enzyme.

This prevents the herpes virus from making new copies of itself, helping existing sores heal faster and reducing the chance of future outbreaks.

When is Genital Herpes Confirmed, and Medication Needed?

Genital herpes is diagnosed by a healthcare professional based on symptoms such as painful blisters or sores, itching, and redness around the genital area, and sometimes by a swab (PCR) test.

Treatment with antivirals like Valtrex is recommended as soon as possible after symptoms appear to shorten the outbreak and relieve discomfort.

Daily suppressive therapy may be offered if outbreaks are frequent.

Trigger factors for recurrences

Stress, fatigue, illness, or a weakened immune system can make future outbreaks more likely.

Can Valtrex Be Purchased Over the Counter?

No. Valtrex is a prescription-only medicine (POM) in the UK.

A registered prescriber must review your medical history before it can be supplied.

Alternative Medications

Aciclovir – works the same way but usually requires more frequent dosing.

Generic valaciclovir – identical active ingredient at potentially lower cost.

Your prescriber will help you choose the most appropriate treatment.

Treatment of an outbreak

Recurrent episode: 500 mg twice daily for 3 days or 1 g once daily for 5 days.

Suppressive (daily) therapy

500 mg once daily (may be increased to 1 g once daily if outbreaks are very frequent).

Take with or without food and drink plenty of water to protect your kidneys.

If you miss a dose, take it as soon as you remember unless it is almost time foryour next dose—never double up.

Follow your prescriber’s instructions carefully.

Active ingredient: valaciclovir hydrochloride.

Inactive ingredients (may vary by manufacturer): microcrystalline cellulose, crospovidone, povidone K30, magnesium stearate, hypromellose, titanium dioxide (E171), polyethylene glycol, indigo carmine aluminium lake (E132).

Common (usually mild): headache, nausea, stomach pain, diarrhoea, dizziness, tiredness.

Serious (seek urgent help via NHS 111 or A&E):

Severe allergic reaction (swelling of face, lips, tongue or throat, difficulty breathing)
Confusion, hallucinations, agitation (more likely in older adults or those with kidney problems)
Signs of kidney issues such as painful or reduced urination or ankle/foot swelling.
Good hydration reduces the risk of kidney-related side effects.