Should you cut metoprolol down when starting ranolazine? and what side effects would this cause if so. what are the side effects of ranolazine?

This medication, used to treat angina,is used along with other medications including beta blockers like metoprolol. It's exact mechanism of action is not known but there's a host of meds that it should not be used with,predominantly those that can prolong the QT interval on the EKG as dangerous arrhythmias could occur. Grapefruit juice & meds using the same enzyme metabolism must be avoided.

We can only give general advice on this forum. This is a question you really need to ask your cardiologist for specific advice about your medication’s for your heart condition.