Valacyclovir 500 mg for genital herpes: three jobs, three schedules

Valacyclovir 500 mg does three separate jobs in genital herpes, and they use three different schedules. Treating an outbreak takes a short high-dose course. Preventing outbreaks takes one tablet a day indefinitely. Reducing the chance of passing the virus to a partner takes the same daily tablet but is measured against a different outcome entirely. Choosing the wrong schedule is the usual reason someone concludes the drug is weak, and the dose that works for one job does nothing for another.

The three schedules

Episodic treatment of a recurrence: 500 mg twice daily for three days, started at the first tingle rather than after the blisters appear. The 72-hour window is not a formality — antivirals work by stopping viral replication, and by the time lesions are established most of the replication has happened. Someone who waits two days to decide whether it is "really" an outbreak has spent the window.

Suppressive treatment: 500 mg once daily, or 1000 mg once daily for people with more than nine recurrences a year. This cuts recurrence frequency by around seventy to eighty per cent and is reviewed annually, because outbreak frequency falls naturally over the years and many people can stop.

Reducing transmission: 500 mg once daily taken by the infected partner. In the serodiscordant-couple trial this roughly halved transmission to the uninfected partner over eight months. It does not eliminate it, which is the number that matters in the conversation that follows a diagnosis.

Why this rather than aciclovir

Valacyclovir is a prodrug of aciclovir with far better oral absorption — bioavailability around fifty-five per cent against ten to twenty per cent. Once in the body it becomes the same molecule and does the same thing. The practical difference is the dosing schedule: twice or once daily instead of five times a day, which is the entire reason it displaced the older drug for genital herpes.

Where cost is the deciding factor, aciclovir is pharmacologically equivalent if taken correctly, and taking it correctly means five doses a day for five days. For a cold sore caught early, aciclovir cream handles it topically. Neither clears the virus; nothing available does.

Prices by strength and pack

Indicative prices in US dollars. A ten-tablet pack covers two episodic courses; the 90 and 120 packs are for daily suppression, where the per-day figure is what counts.

Safety, and the one group that needs care

It is a well-tolerated drug. Headache and nausea are the usual complaints; rash and dizziness are less common. There is no cumulative toxicity over years of suppressive use, which is why indefinite daily dosing is acceptable.

Renal function is the exception that matters. Valacyclovir is cleared by the kidneys, and in impaired function the dose must come down — otherwise levels rise and, at high doses, cause confusion, hallucinations and crystal nephropathy. Dehydration during an acute illness is the common trigger, so drinking properly during a treatment course is practical advice rather than a platitude. In immunosuppressed patients at high doses, a thrombotic microangiopathy has been reported, which is the reason high-dose use in that group is a specialist decision.

What to tell a partner, and what the numbers are

This is the part of a herpes diagnosis that causes more distress than the lesions, and vague reassurance does not help. Three facts carry the conversation. Transmission happens mostly from asymptomatic shedding rather than during a visible outbreak, which is why avoiding sex during flare-ups reduces risk but does not remove it. Condoms reduce transmission by roughly a third to a half, depending on the study and the direction of transmission. Daily suppressive treatment taken by the infected partner roughly halves it again, and the two measures together are additive.

The emotional weight of the diagnosis is usually heavier than the medical one, and it tends to land on sex rather than on health — avoidance, loss of desire, a conviction that disclosure will end any relationship. That is the territory of clinical sexology rather than of antivirals, and at this studio the first consultation is free. The rest of this group is listed under anti viral, and where the exposure risk being discussed is HIV rather than herpes, pre-exposure prophylaxis is a separate and more demanding conversation.

Questions people actually ask

Will it cure herpes?

No. The virus stays in the nerve roots for life. Treatment shortens outbreaks, reduces how often they happen and lowers the chance of passing it on.

When exactly should I start an episodic course?

At the first warning sign — tingling, itching or burning before anything is visible — and within 72 hours at the latest. Keeping a pack at home is what makes that possible.

Is it safe to take every day for years?

Yes, for people with normal kidney function, and the long-term safety data cover years rather than months. The review is annual, because recurrences get less frequent with time.

Does it work for cold sores too?

Yes — the same virus family, a shorter course, usually a single day of higher dosing. Oral and genital herpes are treated with the same molecules on different schedules.

The label these figures come from

Dose schedules, the transmission-reduction data, renal dose adjustment and the microangiopathy warning follow the FDA prescribing information for valacyclovir, and the counselling points follow the CDC sexually transmitted infections treatment guidelines. This page is information, not a prescription.