Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
a light-headed feeling, like you might pass out;
fast or pounding heartbeats, fluttering in your chest; or
kidney problems--little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath.
Common side effects may include:
nausea, constipation;
headache; or
dizziness.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Ranolazine side effects (more detail)
