Drug Interactions With Valacyclovir

As with any medication, there are potential drug interactions with valacyclovir. Combining it with other medications, such as cimetidine, probenecid, or tenofovir, can cause the levels of valacyclovir in your blood to increase. Although drug interactions with valacyclovir do not cause problems for most people, they can increase the risk of side effects in people with poor kidney function.

 

Drug Interactions With Valacyclovir: An Overview

Valacyclovir hydrochloride (Valtrex®) can potentially interact with many drugs. Some of the drugs that may lead to interactions with valacyclovir include:
 

Valacyclovir Interactions Explained

The following paragraphs explain in detail how these drugs can interact negatively with valacyclovir when taken together.
 
Cimetidine
Taking valacyclovir with cimetidine can increase the level of valacyclovir in your blood. For most people, this interaction will not cause any problems, and the doses of these medications do not need to be adjusted. However, your risk of side effects due to this interaction is increased if you have poor kidney function. Talk to your healthcare provider about combining these medications if you have kidney problems.
 
Probenecid
Taking valacyclovir and probenecid together can increase the level of valacyclovir in your blood. However, this interaction is unlikely to cause problems, and the doses of these medications do not need to be adjusted. However, your risk of side effects due to this interaction is increased if you have poor kidney function. Ask your healthcare provider about taking this combination of medicines if you have kidney problems.
(Drug Interactions With Valacyclovir Continued: Page 2)
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Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;