Nonit 20mg Tablet is used to prevent chest pain (angina attacks). It works by relaxing and widening blood vessels so blood can flow more easily to the heart. These tablets will not treat an angina attack that has already begun. They may be also used to control heart failure. Nonit 20mg Tablet should be taken on an empty stomach. It is best taken at the same time every day. Your doctor will decide the dose and the number of times each day you should take them. You should take the medicine as it is prescribed for you and keep taking it, even if you feel well. If you stop taking it suddenly your risk of an angina attack will increase. Lifestyle changes such as diet, exercise, and not smoking may help this drug work better. You can develop tolerance to this medicine over time, which means that the same dose becomes less effective. You have to stick to a really specific dosing schedule to prevent this from happening. The most common side effects of this medicine include headache and lightheadedness. These may disappear once you have got used to the medicine. If you are worried, or the symptoms do not go away, let your doctor know. Some of these can be reduced by taking painkillers, drinking plenty of fluids, and avoiding alcohol. Alcohol may increase some side effects (dizziness, drowsiness, feeling light-headed, or fainting). Medical tests (such as blood pressure) may be required to monitor your progress and check for side effects.