The symptoms of headache after taking Isosorbide mononitrate tablets are caused by the dilation of the small intracranial arteries and cerebral arteries caused by Isosorbide mononitrate tablets, which compress the surrounding tissues. If the pain is more intense, you should follow the advice of cardiology department, you can give a change of medication, change other drugs to improve the blood supply to the heart muscle for treatment. Isosorbide mononitrate is mainly a vasodilator drug, it can mainly dilate the coronary arteries, clinically used to treat coronary heart disease, angina pectoris and other problems, but the use of the beginning should be a small dose to start, so that the impact on the headache can be less, angina pectoris patients take the drug or must do is to use the drug to reduce the headache. However, some people can take isosorbide mononitrate without any headache symptoms.