Let's take a minute to talk about your medication. 

This is isosorbide mononitrate. It works to help prevent chest pain from happening. However, it does not work fast enough to treat chest pain once it occurs. 

It is important to take isosorbide at the exact times that your doctor prescribes. Be careful not to crush or chew the tablet. Also, be sure to drink at least half of a glass of water after swallowing each dose. 

At first, or if your doctor increases your dose, you could feel dizzy. So don't do activities that require you to be alert, like driving, until you know how it affects you. You can reduce dizziness by standing slowly after you've been sitting or lying down. Some patients have daily headaches, which may indicate that this medicine is working. If you get headaches, ask your doctor or pharmacist if it is best to treat them with aspirin or acetaminophen. If these or other side effects become reasons you want to stop taking this medicine, please talk to your doctor or pharmacist. 

This medicine can cause low blood pressure. You can ask your doctor if you should check your blood pressure, and when to report low readings. 

You should not take any medicine for erectile dysfunction, which includes Viagra, Cialis and Levitra. You should also talk to your doctor before drinking alcohol, and before taking other medicines, even if they don't require a prescription. 

As with any medicine, rare but more serious side effects can occur. You should call your doctor right away if you notice any unusual changes to your body, like nausea or cold sweats. 

For best results with isosorbide, let your doctor know right away if your chest pain is not controlled well.