1 What is Dilatrate-SR?

Brand: Dilatrate-SR, Isochron, IsoDitrate, Isordil Titradose

Generic: Isosorbide Dinitrate

Dilatrate-SR is indicated for the prevention and treatment of angina pectoris (chest pain) due to coronary artery disease.

This medicine can be used sublingually at the time of the attack as well as orally for chronic prophylaxis. Regular use of this drug on a long-term basis prevents the recurrence of angina attacks.

Indeed, isosorbide dinitrate belongs to the group of medicines called nitrates. It works by relaxing the vascular smooth muscles and increasing the supply of blood and oxygen to the heart while reducing its workload.

However, because of relatively slower onset of action than that of sublingual nitroglycerin, sublingual ISDN is not the drug of the first choice for the abortion of an acute anginal episode.

This medicine is available only with your doctor's prescription. This product is available in the following dosage forms:

  • Capsule, Extended Release
  • Tablet
  • Tablet, Chewable
  • Tablet, Extended Release

2 What to Know Before Using

Before using Dilatrate-SR, you must know all about the risks and complications associated with it. The suitable drug therapy is usually chosen by a doctor with the active participation of the patient.

There are some important factors such as drug interactions, the presence of any metabolic impairment, history of hypersensitivity reaction, pregnancy, lactation etc. which may alter the desired therapeutic effects of a medicine.

Sometimes the presence of other health disorders affects the beneficial effects of this medicine and even may cause serious toxic effects. If you have had any allergic reactions to any medicine then you must tell your doctor about that.

Allergic reactions to organic nitrates are extremely rare, but they do occur. The use of isosorbide dinitrate (ISDN) is contraindicated in those who are allergic to this drug or any of the ingredients of the formulation.

Make sure you inform your doctor if you have any other medical problems, especially:

Because of drug-drug interactions, certain medicines (e.g., avanafil, riociguat, sildenafil, tadalafil, vardenafil, etc.) should not be used along with this medicine. It is always recommended to consult with your doctor if you are in need of some other medications or even any over-the-counter medicine for another health problem in order to avoid unwanted toxic effects.

Besides, the following drug interactions should be kept in mind:

  • Vasodilatory effects may be reduced with dihydroergotamine.
  • Reduced effectiveness of sublingual form with disopyramide.
  • Increased hypotensive effects with alcohol or vasodilators.
  • Significant hypotension may occur with phosphodiesterase-5 inhibitors.
  • Marked orthostatic hypotension may occur when used with calcium channel blockers.
  • Sildenafil causes dangerous potentiation of nitrate action: severe hypotension, MI, and deaths are on record.

Animal reproduction studies have shown an adverse effect, and there are no adequate and well-controlled studies in pregnant women. Thus, this drug should be used during pregnancy only if clearly needed.

Besides, caution should be exercised when used in lactating women because there are no adequate studies in women for determining infant risk when using this medication during breastfeeding.

3 Proper Usage

To use Dilatrate-SR properly, you must follow all instructions given by your doctor. The dosage schedule and the duration of drug therapy should be individualized and determined based on the physician’s advice.

The therapeutic dose may also vary with the patient’s condition or requirement and the strength of the medicine as well; however, different preparations and dosages for angina prevention are listed below:

For oral dosage forms (extended-release tablets or sustained-release capsules):

  • Adults— initially, 40 mg twice daily. Your doctor may increase your dose as needed. However, the dose should not be more than 160 mg per day.
  • Children— use and dose must be determined by your doctor.

For oral dosage form (tablets):

  • Adults— initially, 5 to 20 mg two or three times a day. Your doctor may increase your dose as needed.
  • Children— use and dose must be determined by your doctor.

For sublingual dosage form (tablets):

  • Adults— 2.5 to 5 mg about 15 minutes before expected physical or emotional stress.
  • Children— use and dose must be determined by your doctor.

If you miss a dose of this medicine, take it as soon as possible. But, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not use this drug in larger amounts, more often, or for a longer time than your doctor ordered.

Further, it is advised to store the medicine in a closed container at room temperature away from heat, moisture, and direct light. All kinds of medicines should be kept out of the reach of children. However, outdated medicines should be disposed by an appropriate way.

4 Precautions to Take

Before using Dilatrate-SR, there are some precautions you must take. Firstly, regular visits to your doctor are recommended to check that this medicine is working properly or not.

Additionally, the following guidelines should be followed to prevent unwanted complications as well as for the better prognosis of the patients:

Severe hypotension, particularly with upright posture, may occur with even small doses of isosorbide dinitrate. This drug should, therefore, be used with caution in patients who may be volume depleted or who, for whatever reason, are already hypotensive. Hypotension induced by isosorbide dinitrate may be accompanied by paradoxical bradycardia and increased angina pectoris.

Nitrate therapy may aggravate angina caused by hypertrophic cardiomyopathy.

In industrial workers who have had long-term exposure to unknown (presumably high) doses of organic nitrates, tolerance clearly occurs.

Do not take avanafil (Stendra®), riociguat (Adempas®), sildenafil (Viagra®), tadalafil (Cialis®), or vardenafil (Levitra®) while you are using this medicine. Using these medicines together may cause blurred vision, dizziness, lightheadedness, or fainting. If you are taking these medicines and you experience an angina attack, you must go to the hospital right away.

This medicine may cause headaches. These headaches are a sign that the medicine is working. Do not stop using the medicine or change the time you use it in order to avoid the headaches. If you have severe pain, talk with your doctor.

Dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking this medicine, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for long periods of time.

Do not stop using this medicine without checking first with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping it completely.

5 Potential Side Effects

As with many medications, there are several potential side effects associated with Dilatrate-SR. These side effects usually go away during the treatment episode as your body adjusts to the medicine.

Your healthcare professional may advise you about the ways how to prevent or reduce those unwanted side effects.

Sometimes you may need to consult with the doctor if you notice any of the following toxic effects:

  • The fullness of head, throbbing headache; some degree of intolerance develops on continued use.
  • Flushing, weakness, sweating, palpitation, dizziness, and fainting; these are migrated by lying down. Erect posture and alcohol accentuate these symptoms.
  • Methemoglobinemia is not significant with clinically used doses. However, in severe anemia, this can further reduce oxygen carrying capacity of blood.
  • Rashes may occur but rarely.

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.