Ranolazine 500mg Tablet ER is used for the management of angina (heart-related chest pain). It helps to prevent new attacks of angina but does not stop an acute attack, once started. It relieves chest pain by making the heart work more efficiently. Ranolazine 500mg Tablet ER should be taken in the dose as advised by your doctor, at the same time each day. It should be taken with food to avoid stomach upset. Your doctor will decide how often you should take this medicine. This may change from time to time depending on how well it is working. You should take this medicine regularly to get the most benefit, even if you feel fine. It is preventing future harm. If you stop taking it, your chest pain may come back.