Patients who know their condition usually carry prescribed medications to relieve pain, such as nitroglycerin. If the patient requests, help him take this medicine. They are available in the form of small tablets, one of which must be placed under the tongue, an aerosol sprayed into the oral cavity, and also in the form of a patch for sticking to the chest. Nitroglycerin causes blood vessels to dilate, which increases blood flow to the heart. Nitroglycerin usually takes a few seconds to take effect and may cause a headache. The patient must sit or lie down while taking the medicine.