Drug Interaction Report

Using ranolazine together with fosphenytoin is not recommended. Combining these medications may significantly reduce the blood levels of ranolazine, which may make the medication ineffective or less effective. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

You may take ranolazine with or without food, but should try to take it the same way every time. Grapefruit and grapefruit juice should be avoided if possible. Grapefruit juice can increase the levels of ranolazine in your body. High blood levels of food can occasionally cause an irregular heart rhythm that may be serious. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, or fast or pounding heartbeats during treatment with ranolazine. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.