Burning Sensation and Potency of Nitroglycerin Sublingually

Abstract

The unwitting use of deteriorated nitroglycerin confuses the diagnosis and treatment of angina pectoris. Knowledge of the potency of each tablet at the time of its use would eliminate the confusion. The clinical impression that fresh nitroglycerin causes a burning sensation that provides a practical index of potency was tested. Thirty inexperienced subjects were tested in a double-blind study with fresh and artificially aged nitroglycerin. Twenty-seven reported immediate sublingual burning with fresh drug and decreased or absent burning with aged tablets (<i>P</i>&lt;0.001). Surprisingly, the faint sweetness of nitroglycerin, a true taste sensation, had no value as an index of freshness. Fresh drug caused more systemic effect (<i>P</i>&lt; 0.001), and this correlated with burning sensation (<i>P</i>&lt; 0.02 and<i>P</i>&lt; 0.001). Localized sublingual erythema and vasodilatation occurred simultaneously with burning, suggesting that the burning sensation indicates potency by reflecting topical activity.