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Generic name: isosorbide dinitrate [EYE-soe-SOR-bide-dye-NYE-trate]

Brand names: Isochron, Isordil Titradose
Drug class: antianginal agents

What is Isochron?

Isochron, a nitrate, dilates blood vessels (widens them), making it easier to flow blood through and for the heart to pump. Use of isochron to treat or prevent chest pain (angina)

The sublingual tablet is the only treatment for angina attacks that have already started.

The tablets Isochron Regular and Extended-Release are used to treat angina but not to prevent it. This medication guide does not list all possible uses of isochron.

Side effects of Isochron

If you experience any of the following symptoms of an allergic reaction, seek immediate medical attention: hives, difficulty breathing, swelling of your lips, face, or throat.

Isochron may cause serious side effects. If you experience:

  • A feeling of lightheadedness, as if you could pass out.
  • Worsening angina pain;
  • Fast heart rate or slow heart rate?
  • You may feel your heart pounding or your chest fluttering.

Isochron may cause severe headaches. As you continue to use nitroglycerin, these headaches may become less severe. Isochron should not be stopped to prevent headaches. Before taking any headache medication, consult your doctor.

Side effects that are more common include:

  • Headache
  • Flushing (warmth, redness, or tingly sensation)

There may be other side effects. For medical advice on side effects, call your doctor. The FDA can be contacted at 1-800-FDA-1088 to report side effects.

Similar/related drugs

Amlodipine, Metoprolol, Aspirin, Carvedilol, Propranolol, Atenolol, and Diltiazem


Isochron should not be taken with erectile dysfunction medicine (Viagra, Cialis, Levitra, Stendra, Staxyn, sildenafil, avanafil, tadalafil, and vardenafil). Combining these medicines can lead to a rapid and severe drop in blood pressure.

If you experience early signs of a heart attack, such as chest pain, pressure or pain that spreads to your shoulder or jaw, excessive sweating, or a general feeling of unwellness, seek emergency medical care.

Take this medication only if you have been prescribed it.

Isochron should not be used if you:

  • You are allergic to isochron, isosorbide mononitrate,
  • You have early signs of a heart attack. (Chest pain or pressure; pain that spreads to your shoulder or jaw; nausea and sweating)

Isochron should not be taken with erectile dysfunction medicine (Viagra, Cialis, Levitra, Stendra, Staxyn, sildenafil, avanafil, tadalafil, and vardenafil). Combining these medications can result in a rapid and severe drop in blood pressure.

Tell your doctor about any of the following to ensure that isochron will be safe for you:

  • Congestive heart failure;
  • Kidney disease
  • Low blood pressure.

Isochron may harm a baby in utero.Inform your physician immediately if you are pregnant or planning on becoming pregnant.

It is unknown if isosorbide dinitrate can pass into breast milk or if this could affect nursing babies. Inform your doctor if breastfeeding is taking place.

How to take Isochron?

Your doctor may recommend that you use a sublingual nitroglycerin tablet before using isochron for a sudden attack of angina. You should follow your doctor's directions on what medication to take during an attack and how long to wait between doses.

Please follow all the instructions on the prescription label. Your doctor may occasionally alter your dosage. Take this medication only as prescribed. Do not exceed the recommended dose or take it longer. You may not be able to control your condition if you take too much isochron.

When taking this medication, try to stay seated or rest (this may cause nausea or fainting). Isochron can be taken regularly to prevent angina attacks. Use the medication at the first sign that you feel chest pain to treat angina. Place the tablet on your tongue and let it dissolve slowly. These materials should never be chewed or swallowed.

Use the sublingual tablet 15 minutes prior to any activity that you suspect may cause chest pain. You should follow your doctor's advice. Do not open, crush, chew, or break a capsule or tablet. Swallow the capsule whole.

Do not forget to follow your doctor's instructions. Your dosage may need to change if your doctor changes the brand, strength, or type of isosorbide dinitrate. If you have questions about a new type of isosorbide diuretic you received at the pharmacy, ask your pharmacist.

If your chest pain becomes worse or persists for more than five minutes, seek emergency medical care, especially if it is accompanied by difficulty breathing, nausea, dizziness, or weakness.

This medicine may cause very low blood pressure. If you have diarrhea or vomiting or are sweating excessively, call your doctor. Isochron can be dangerous if you have a severe electrolyte imbalance due to prolonged illness.

Do not suddenly stop taking isochron if you are regularly taking it to prevent angina. You could suffer a severe angina attack. Always keep this medication on hand. Refill your prescription before you run out. Store away from heat, moisture, and light. When not in use, keep the bottle tightly shut.

What happens if I miss the dose?

You may not have a schedule for Isochron because it is used when necessary. If you have a regular schedule, you should take the missed dosage as soon as possible. If your next dose is within 2 hours, skip the missed dose.

You can skip the missed dose if your next scheduled dose is within 6 hours.Don't use extra medication to make up for a missed dosage.

What happens if you overdose?

If you believe you've used too much isochron, seek emergency medical care. A fatal overdose of isosorbide can occur if you take too much isochron.

Overdose symptoms include a severe headache, fever, confusion, dizziness or severe vertigo, heart palpitations, vision problems or blurred vision, nausea, vomiting, or stomach pains, bloody diarrhea, or other symptoms such as trouble breathing or sweating. Other symptoms are cold skin, cold sweat, or fainting.

What should be avoided?

This medicine can impair your reactions or thinking. You should be careful when driving or doing anything else that requires you to remain alert. You may get dizzy if you stand up quickly from a seated or lying position. To avoid a fall, get up slowly.

Avoid alcohol. Alcohol can increase the side effects of isosorbide (dizziness or drowsiness), as well as other symptoms.

Interaction with other drug

Isochron can cause dangerously low blood pressure when taken with certain other medications. These include medicines used to treat erectile dysfunction or pulmonary arterial hypotension. There may be serious, even life-threatening side effects.

Tell your doctor if you are taking any new medications or if you will stop using any of your current ones.

  • Avanafil (Stendra);
  • A diuretic, or "water pill".
  • Nitroglycerin;
  • Riociguat (Adempas);
  • Sildenafil (Viagra, Revatio);
  • Tadalafil, Adcirca (Cialis);
  • Vardenafil (Levitra, Staxyn).

This list is incomplete. There are other drugs that may interact with isosorbide dinitrate. These include prescription and over-the-counter medicines, vitamins, and herbal products. This medication guide does not list all possible interactions.