Home » Anti Fungal & Antiviral » Valtrex
Brand names: Valtrex, Aciclovier, Aciclovir, Acyclovir, Avirax, Valaciclovir, Valacivir, Valcivir, Vipral, Virorax
Generic name: Valaciclovir
NB: This is brand Valtrex. NOT a generic product!
What is Valtrex used for:
Valtrex (Valacyclovir/Valaciclovir) is an oral daily therapy prescribed for genital herpes, cold sores or shingles. It doesn't cure herpes, but reduces the number of outbreaks and may lower the risk of passing on the virus
How does Valtrex work?
Valtrex tablets contain the active ingredient valaciclovir. Valaciclovir is known as a pro-drug. Once inside the body it is broken down into the active ingredient aciclovir, which is an antiviral medicine used to treat infections with herpes viruses. These include the viruses that cause cold sores and genital herpes (herpes simplex 1 and 2) and the virus that causes chickenpox and shingles (varicella zoster or herpes varicellae). Aciclovir works by stopping these herpes viruses from reproducing and infecting more cells in the body.
Aciclovir is converted to a more active form inside cells of the body that are infected with herpes viruses. The activated aciclovir then works by blocking the action of a viral enzyme called DNA polymerase.
The herpes viruses need the DNA polymerase enzyme to copy their genetic material from RNA to DNA. This process is necessary for the viruses to multiply and continue to survive. By blocking the action of DNA polymerase, aciclovir prevents the herpes viruses from multiplying. This controls the infection and helps the immune system to deal with it.
Valaciclovir is taken by mouth to treat herpes infections that cause shingles (herpes zoster). It is also taken to treat herpes simplex infections of the skin and mucous membranes, including genital herpes. Valaciclovir can be used to treat recurrent flare-ups of herpes simplex infection. It is most effective at preventing the sores from developing if treatment is started as soon as the warning signs appear.
If you suffer from frequent herpes simplex flare-ups your doctor may prescribe valaciclovir for you to take regularly, to suppress the virus and prevent recurrences. Valaciclovir taken regularly can also reduce the risk of passing the genital herpes to a sexual partner, provided safe sex practices such as condoms are used as well. However, you should still avoid sexual contact when the sores are present to avoid passing on the virus.
Valaciclovir has a further use in preventing infection with cytomegalovirus (CMV) in people who have had a kidney transplant. CMV is another member of the herpes group of viruses. In healthy people this common virus normally produces symptoms milder than the common cold, but in people whose immune systems are compromised it can cause serious infection because the immune system cannot fight it.
People who have had kidney transplants are given powerful medicines that suppress the immune system in order to stop it attacking the transplanted organ. However, because they suppress the immune system, these medicines also suppress the ability of the body to fight infection. Valaciclovir is therefore given to people who have received a kidney transplant, in order to help the body kill off any CMV virus.
What is Valtrex used for?
* Genital herpes (herpes simplex infection)
* Herpes simplex infections of the skin, eg cold sores
* Preventing recurrence of herpes simplex infections, eg recurrent cold sores or genital herpes
* Reducing the risk of spreading genital herpes to a sexual partner (when used with safe sex practices such as using condoms)
* Prevention of cytomegalovirus (CMV) infection in people who have had a kidney transplant
* Shingles (herpes zoster)
* If you are at risk of becoming dehydrated it is important to drink plenty of fluids while taking this medicine.
* When this medicine is used for genital herpes it does not provide a cure, or completely eliminate the risk of passing the virus to a sexual partner. You should continue to practice safe sex, particularly the use of condoms, in addition to taking this medicine. You should also avoid sexual contact while the sores are present.
Use with caution in
* Decreased kidney function
* Decreased liver function
Not to be used in
* Allergy to aciclovir or valaciclovir
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and Breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
* This medicine should be used with caution during pregnancy, and only if the expected benefit to the mother is greater than any possible risk to the foetus. Seek medical advice from your doctor.
* This medicine passes into breast milk. It should be used with caution by breastfeeding mothers and only if the expected benefit to the mother is greater than any possible risk to the nursing infant. Seek medical advice from your doctor.
* Take at regular intervals. Complete the prescribed course unless otherwise directed.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
* Abdominal pain
* Abnormal reaction of the skin to light, usually a rash (photosensitivity)
* Decreased kidney function
* False perceptions of things that are not really there (hallucinations)
* Nausea and vomiting
* Decrease in the number of platelets in the blood (thrombocytopenia)
* Skin reactions such as rash and itch
* Disturbances of liver function
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
The blood level of this medicine may be increased by the following medicines:
This is not normally clinically important. However, where high doses of valaciclovir are being used to prevent CMV infection following a kidney transplant, your doctor may consider using alternatives to these medicines, or simply monitor you more closely.