Drug interactions between ranexa (ranolazine) and diltiazem?

Yes. Diltiazem interacts with Ranexa (ranolazine) in the liver and increases its level in the blood stream. Can prolong qt and cause rythm disturbances. Other side effects from renexa likely: constipation, dizziness, headache, nausea., palpitations, dizziness and blurred vision. These are more likely with this combination, but many people on this combination of drugs. Double check with your doctor.
Here's a link... Consider checking this: http://www.drugs.com/drug_interactions.php.
Always good to check. You can use a drug interaction checker whenever you have questions about drug-drug interactions or drug - food interactions. Here is 1 option (Drugs.Com): https://www.drugs.com/drug_interactions.php Your pharmacist is also a good source of info.