Instructed patient on isorsobide which is used to treat and prevent chest pain, side effects of isorsobide are headache, dizziness, lightheadedness, nausea or vomiting. Headache is often a sign that this medication is working; treat it with an aspirin or non-aspirin pain reliever as recommended by your doctor. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.