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Valaciclovir for viral infections

Valtrex

You can take valaciclovir tablets either with or without food.

Space out your doses evenly over the day, and complete the full course of treatment.

Drink plenty of water. It is important that you don't become lacking in fluid in the body (dehydrated).

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About valaciclovir

Tipo de medicamento

Un medicamento antivírico

Utilizado para

To prevent or treat viral infections in adults and in young people

También llamado

Valacyclovir (in US); Valtrex®

Disponible como

Tabletas

Valaciclovir is known as a pro-drug. Once inside your body it is broken down into an active ingredient called aciclovir. It is used to treat infections caused by two common viruses - herpes zoster and herpes simplex. The herpes zoster virus is the cause of shingles. Herpes simplex viruses cause cold sores, and genital herpes. You will have been prescribed valaciclovir to treat (or prevent further episodes of) one of these infections.

Valaciclovir works by preventing viruses from multiplying, and this reduces the severity of the infection and stops it from spreading.

As well as treating infections, valaciclovir is also prescribed to prevent some viral infections from occurring. This is particularly the case in people who have had an organ transplant and are at risk of infection from a virus called cytomegalovirus.

Before taking valaciclovir

Some medicines are not suitable for people with certain conditions, and sometimes a medicine can only be used if extra care is taken. For these reasons, before you start taking valaciclovir it is important that your doctor knows:

  • Si está embarazada o en periodo de lactancia.

  • Si tiene algún problema con el funcionamiento de sus riñones.

  • Si toma o utiliza otros medicamentos. Esto incluye cualquier medicamento que esté tomando y que pueda adquirirse sin receta, así como medicamentos a base de plantas y complementarios.

  • Si alguna vez ha tenido una reacción alérgica a un medicamento.

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How to take valaciclovir

  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about valaciclovir, and it will also provide you with a full list of the side-effects which you could experience from taking it.

  • Your dose will depend upon the type of infection you have, so take the tablets exactly as your doctor tells you to. Typically, doses range from 500 mg to 2 g, taken 1-4 times daily. Your doctor or pharmacist will tell you what dose is right for you, and this information will also be printed on the label of the pack to remind you about what the doctor said to you.

  • Space out your doses evenly during the day. Swallow the tablets with a drink of water. You can take valaciclovir tablets either with or without food.

  • Even if you feel your infection has cleared up, keep taking valaciclovir until the course is finished (unless your doctor tells you to stop sooner). A short course of treatment commonly lasts for up to 10 days. You will be prescribed a longer course than this if you are taking it to prevent further episodes of infection, or following an organ transplantation.

  • If you forget to take a dose, take it as soon as you remember and then continue as before. Try to take the correct number of doses each day, but do not take two doses at the same time to make up for a missed dose.

Aproveche al máximo su tratamiento

  • You should drink plenty while you are on valaciclovir to keep your kidneys working well. Drinking water is best, but hot drinks and non-alcoholic cold drinks are also suitable.

  • Valaciclovir could cause your skin to become more sensitive to sunlight than it is usually. Avoid strong sunlight and sunbeds, and use a sun cream with a high sun protection factor until you know how your skin reacts.

  • If you have been prescribed valaciclovir for genital herpes, do not have sex while you have sores or blisters. Even after these have healed, there is still a small chance that you may pass on the virus when you have sex - using a condom reduces this risk.

  • If you are having an operation or any other medical treatment, tell the person carrying out the treatment that you are taking valaciclovir.

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Can valaciclovir cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the more common ones associated with valaciclovir. The best place to find a full list of the side-effects which can be associated with your medicine, is from the manufacturer's printed information leaflet supplied with the medicine. Alternatively, you can find an example of a manufacturer's information leaflet in the reference section below. Speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common valaciclovir side-effects

(afectan a más de 1 de cada 10 personas)

¿Qué puedo hacer si me ocurre esto?

Dolor de cabeza

Bebe mucha agua y pide a tu farmacéutico que te recomiende un analgésico adecuado. Si los dolores de cabeza persisten, consulte a su médico.

Common valaciclovir side-effects

(afectan a menos de 1 de cada 10 personas)

¿Qué puedo hacer si me ocurre esto?

Sentirse mal (náuseas) o estar enfermo (vómitos)

Coma alimentos sencillos: evite las comidas grasas o picantes.

Sensación de mareo

No conduzca ni utilice herramientas o máquinas mientras esté afectado

Diarrea

Beber mucha agua para reponer los líquidos perdidos

Itching or skin rash

En caso de molestias, hable con su médico

Si experimenta cualquier otro síntoma que considere que puede deberse al medicamento, consulte a su médico o farmacéutico.

How to store valaciclovir

  • Mantenga todos los medicamentos fuera del alcance y de la vista de los niños.

  • Almacenar en un lugar fresco y seco, lejos del calor y la luz directos.

Información importante sobre todos los medicamentos

Información importante sobre todos los medicamentos

No tome nunca más de la dosis prescrita. Si sospecha que usted u otra persona ha tomado una sobredosis de este medicamento, acuda al servicio de urgencias de su hospital. Llévese el envase, aunque esté vacío.

Este medicamento es para usted. Nunca se lo dé a otras personas aunque su enfermedad parezca ser la misma que la suya.

Si compra algún medicamento, compruebe con un farmacéutico que es adecuado para tomarlo con sus otros medicamentos.

No guarde medicamentos caducados o que no desee. Llévelos a su farmacia local, que se encargará de eliminarlos por usted.

Si tiene cualquier duda sobre este medicamento pregunte a su farmacéutico.

Informar de los efectos secundarios de un medicamento o vacuna

Si experimenta efectos secundarios, puede notificarlos en línea a través del sitio web de la Tarjeta Amarilla.

Lecturas complementarias y referencias

Historia del artículo

La información de esta página ha sido redactada y revisada por médicos cualificados.

  • Fecha límite de la próxima revisión: 18 dic 2025
  • 19 dic 2022 | Última versión

    Última actualización

    Michael Stewart, MRPharmS

    Revisado por expertos

    Sid Dajani
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