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.