MINITRAN- nitroglycerin patch
3M Pharmaceuticals
DESCRIPTION
Nitroglycerin is a 1,2,3-propanetriol trinitrate, an organic nitrate whose structural formula is
Image from Drug Label Content
and whose molecular weight is 227.09. The organic nitrates are vasodilators, active on both arteries and veins.
The MINITRAN� (nitroglycerin) Transdermal Delivery System is a unit designed to provide continuous controlled release of nitroglycerin through intact skin. The rate of release of nitroglycerin is linearly dependent upon the area of the applied system; each cm2 of applied system delivers approximately 0.03 mg of nitroglycerin per hour. Thus, the 3.3, 6.7, 13.3 and 20 cm2 system delivers approximately 0.1, 0.2, 0.4 and 0.6 mg of nitroglycerin per hour, respectively.
The remainder of the nitroglycerin in each system serves as a reservoir and is not delivered in normal use. After 12 hours, for example, each system has delivered about 14% of its original content of nitroglycerin.
The MINITRAN Transdermal Delivery System contains nitroglycerin as the active component. The remaining components of the system (acrylate copolymer adhesive, fatty acid esters, and polyethylene backing) are pharmacologically inactive. Each patch is packaged in foil/polymer film laminate.
Prior to use, a protective peel strip is removed from the adhesive surface. Following use, the patch should be discarded in a manner that prevents accidental application or ingestion by children or others.
CLINICAL PHARMACOLOGY
The principal pharmacological action of nitroglycerin is relaxation of the vascular smooth muscle and consequent dilatation of peripheral arteries and veins, especially the latter. Dilatation of the veins promotes peripheral pooling of blood and decreases venous return to the heart, thereby reducing left ventricular end-diastolic pressure and pulmonary capillary wedge pressure (preload). Arteriolar relaxation reduces systemic vascular resistance, systolic arterial pressure, and mean arterial pressure (afterload). Dilatation of the coronary arteries also occurs. The relative importance of preload reduction, afterload reduction, and coronary dilatation remains undefined.
Dosing regimens for most chronically used drugs are designed to provide plasma concentrations that are continuously greater than a minimally effective concentration. This strategy is inappropriate for organic nitrates. Several well-controlled clinical trials have used exercise testing to assess the anti-anginal efficacy of continuously-delivered nitrates. In the large majority of these trials, active agents were indistinguishable from placebo after 24 hours (or less) of continuous therapy. Attempts to overcome nitrate tolerance by dose escalation, even to doses far in excess of those used acutely, have consistently failed. Only after nitrates have been absent from the body for several hours was their anti-anginal efficacy restored. INDICATIONS AND USAGE
Transdermal nitroglycerin is indicated for the prevention of angina pectoris due to coronary artery disease. The onset of action of transdermal nitroglycerin is not sufficiently rapid for this product to be useful in aborting an acute attack.