Drug Interactions With Acyclovir

When certain medications are combined, there is a possibility for drug interactions. With acyclovir, interactions can occur when it is taken with Dilantin, Benemid, or a number of other medications. These may affect the drug levels in your blood and increase your risk of side effects. If drug interactions with acyclovir are a concern, your healthcare provider may adjust your dosages, if necessary.

Acyclovir Medication Information

Drug Interactions With Acyclovir: An Overview

Acyclovir (Zovirax^®) can potentially interact with other medications. Some of the medicines that may lead to drug interactions with acyclovir include:

Phenytoin (Dilantin^®, Phenytek^®) or fosphenytoin (Cerebyx^®)
Probenecid (Benuryl^®, Benemid^®, ColBenemid^®)
Tenofovir (Viread^®).

Acyclovir Interactions Explained

The following sections explain in detail the potentially negative interactions that can occur when acyclovir is combined with any of the drugs listed above.

Phenytoin or Fosphenytoin

There have been reports that acyclovir may decrease the level of phenytoin in your blood, perhaps making it less effective. Your healthcare provider may need to measure the level of phenytoin in your blood (using a blood test) and adjust your dose as necessary.

Probenecid

Probenecid can increase the level of acyclovir in your blood, increasing your risk of acyclovir side effects. Your healthcare provider may need to decrease your acyclovir dosage to prevent this interaction from occurring.

Tenofovir

Acyclovir can increase the level of tenofovir in your blood, potentially increasing your risk of side effects. Your healthcare provider may need to lower your tenofovir dosage to prevent drug interactions from occurring.

(Drug Interactions With Acyclovir Continued: Page 2)