Valtrex vs. Valcyte

Valtrex is an antiviral drug used to treat shingles, genital herpes, and cold sores. It mimics a building block of DNA and stops the spread of the herpes virus in the body. Valtrex is active against the same viruses as acyclovir, but it has a longer duration of action.

Valcyte is used to prevent disease caused by cytomegalovirus (CMV) in transplant and cancer patients. It helps control CMV retinitis and decrease the risk of blindness.

Side Effects

Valtrex

Common side effects include headache, nausea, vomiting, abdominal pain, and cold symptoms. More serious side effects include CNS side effects, increased heart rate, seizures, and decreased blood platelets.

Valcyte

Valcyte can cause serious side effects, including blood and bone marrow problems, kidney failure, fertility problems, and birth defects.

Question

Dosage

Valtrex

Dosage varies based on the condition being treated. It may be taken with or without food. The dose for shingles is 1 gram 3 times a day for 7 days. The dose for genital herpes is 1 gram twice daily for 10 days. The dose for cold sores is 2 grams every 12 hours for 1 day.

Valcyte

Take Valcyte exactly as directed by your doctor. It should be taken with food. Do not break or crush the tablets. If using the oral solution, use the dispensers provided. Avoid contact with the contents and seek medical help if too much is taken.

Drug Interactions

Valtrex

Probenecid and cimetidine may increase the concentrations of Valtrex in the blood, potentially leading to side effects.

Valcyte

Valcyte can harm the kidneys, especially when used with certain other medicines, including antivirals, chemotherapy drugs, and pain medications. It is important to discuss all medications with your doctor.

Safety During Pregnancy and Breastfeeding

Valtrex

Valtrex should only be used during pregnancy if benefits outweigh risks. It is not known if Valtrex is excreted in breast milk, but concentrations of acyclovir in breast milk are higher than in the blood.

Valcyte

Valcyte can cause birth defects in animals. The safety of Valcyte during pregnancy and breastfeeding is not established. Effective birth control should be used during treatment.

Summary

Valtrex and Valcyte are antiviral drugs used to treat different conditions. Valtrex is used for herpes infections, while Valcyte is used to prevent and treat CMV disease.