Oral nitrate preparations: an update

Oral nitrates are used in the treatment of angina and congestive heart failure. In 1993, more than 12 million prescriptions for chronic administration of oral nitrates were written in the United States. Three nitrate compounds are currently available on the U.S. market: nitroglycerin, isosorbide dinitrate and the most recent, isosorbide mononitrate. Oral nitrates are available in sublingual, translingual (spray), transmucosal, chewable or sustained-release forms. Despite the complexity of choices, therapy can be simplified and remain efficacious, provided that attention is given to circumventing tolerance, a challenging problem with nitrate therapy. Tolerance can be avoided by ensuring that there is a daily nitrate-free interval using eccentric (i.e., 8 A.M. and 2 P.M.), twice-daily dosing of standard or sustained-release forms, or frequent intermittent low dosages.