Drugs Home > Drug Interactions With Granisetron
Medications that may cause drug interactions with granisetron include phenobarbital and ketoconazole. While phenobarbital may decrease the level of granisetron in your blood and make it less effective, ketoconazole can increase the level of granisetron in your body and increase your risk of side effects. Reduce your chance of developing negative granisetron interactions by telling your healthcare provider about all other medications you are taking.
Granisetron hydrochloride (Kytril®) can potentially interact with a few other medications. Some of these medicines that may lead to granisetron interactions include:
- Ketoconazole (Nizoral®)
- Phenobarbital (Luminal®)
- Medications that can cause a heart rhythm change known as QT prolongation (see QT-Prolonging Medications for a list of such medications).
The following sections explain in detail the potentially negative interactions that can occur when granisetron is combined with any of the drugs listed above.
Ketoconazole may decrease your body's ability to metabolize granisetron, which could increase the level of granisetron in your blood. This, in turn, could increase your risk of granisetron side effects. Talk to your healthcare provider before using ketoconazole and granisetron together.
Studies have shown that phenobarbital can decrease the level of granisetron in your blood by 25 percent, perhaps making it less effective. Your healthcare provider may need to adjust your granisetron dosage, although this may not be necessary.
There have been reports of a certain change in heart rhythm (known as QT prolongation) in people taking granisetron. This heart rhythm change can be dangerous. Check with your healthcare provider before combining granisetron with other QT-prolonging medications.