Clinical Q & A—Sublingual nitroglycerin: Are we counseling patients properly?

A: For many years, sublingual (SL) nitroglycerin has been used as part of the standard of care in the management of acute anginal episodes. Traditionally, patients prescribed SL nitroglycerin were advised to promptly dissolve one tablet under the tongue or in the buccal pouch at the first sign of an anginal attack. This dose was to be repeated every five minutes for a maximum of three doses. Patients were instructed to contact emergency medical services (EMS) if symptoms were not relieved after three doses, since continuous chest pain or discomfort may be suggestive of a myocardial infarction (MI).

It has been documented, however, that self-treatment with prescription medications, including nitrates, and with over-the-counter products, such as antacids, is a frequent cause of delayed definitive treatment in patients with MI. The rate of use of these medications and the number of doses taken has been positively correlated with a delay in time-to-hospital arrival.

Thus, in 2004, the American College of Cardiology (ACC) and the American Heart Association (AHA) revised the 1999 guidelines for the management of patients with acute myocardial infarction. In these latest guidelines the authors emphasize the importance of early recognition of an MI and activation of the EMS system.

Our search of the pharmacy literature found that this new recommendation has not been well publicized, nor is it reflected in the prescribing information (PI) of several sublingual nitroglycerin products. It is therefore important that pharmacists become familiar with these changes in order to ensure optimal outcomes for patients.

The ACC/AHA practice guidelines for the management of patients with MI, which include the new recommendation on sublingual nitroglycerin, can be accessed at the following Web site: http:// http://www.acc.org/clinical/guidelines/stemi/Guideline1/index.htm

Another recent change concerning the proper use of sublingual nitroglycerin involves the expiration date of the product. Traditionally, pharmacists have counseled patients to discard the SL nitroglycerin product six months after its initial use due to loss of potency. However, SL nitroglycerin has been reformulated to produce greater product stability. As such, when stored at the specified conditions, i.e., in the original container and at room temperature, protected from heat, light, and moisture, SL nitroglycerin maintains its potency until the expiration date specified by the manufacturer. Patients should be advised not to transfer the tablets to another container and to tightly seal the container after each use.

In addition to proper dosage, administration, and storage, several other counseling tips should also be provided when dispensing SL nitroglycerin:

For comprehensive patient counseling on this and other medications, pharmacists may refer to the drug information feature on the National Library of Medicine's Web site, available at: http:// http://www.nlm.nih.gov/medlineplus/druginformation.html.

References available upon request

The authors of this article are Joseph P. Nathan, M.S., Pharm.D., Assistant Professor of Pharmacy Practice; Tina Koumis, Pharm.D., Drug Information Specialist, Adjunct Assistant Professor of Pharmacy Practice; and Jack M. Rosenberg, Pharm.D., Ph.D., Professor of Pharmacy Practice and Pharmacology, Director, International Drug Information Center, Arnold & Marie Schwartz College of Pharmacy and Health Sciences, Long Island University, Brooklyn, N.Y.