The resultant increases in coronary blood flow (epicardial and subendocardial) occur in ischemic and nonischemic models and are accompanied by dose- dependent decreases in systemic blood pressure and decreases in peripheral resistance. Diltiazem produces relaxation of coronary vascular smooth muscle and dilation of both large and small coronary arteries at drug levels that cause little or no negative inotropic effect. It causes excitation-contraction uncoupling in various myocardial tissues without changes in the configuration of the action potential. In animal models, diltiazem interferes with the slow inward (depolarizing) current in excitable tissue. Spontaneous and ergonovine-induced coronary artery spasms are inhibited by diltiazem. Diltiazem has been shown to be a potent dilator of coronary arteries, both epicardial and subendocardial. This is accomplished via reductions in heart rate and systemic blood pressure at submaximal and maximal workloads. The magnitude of blood pressure reduction is related to the degree of hypertension thus hypertensive individuals experience an antihypertensive effect, whereas there is only a modest fall in blood pressure in normotensives.Īngina : Diltiazem hydrochloride extended-release capsules have been shown to produce increases in exercise tolerance, probably due to its ability to reduce myocardial oxygen demand. Hypertension : Diltiazem hydrochloride extended-release capsules produce its antihypertensive effect primarily by relaxation of vascular smooth muscle and the resultant decrease in peripheral vascular resistance. The therapeutic effects of diltiazem hydrochloride extended-release capsules are believed to be related to its ability to inhibit the cellular influx of calcium ions during membrane depolarization of cardiac and vascular smooth muscle. Diltiazem hydrochloride extended-release capsule, USP is formulated as a once-a-day extended-release capsule containing 120 mg, 180 mg, 240 mg, 300 mg, or 360 mg diltiazem hydrochloride.Ĭapsules also contain: hypromellose, sucrose, starch (maize), methacrylic acid and ethyl acrylate copolymer, triethyl citrate, talc, hydroxypropylcellulose, ammonio methacrylate copolymer, ethylcellulose, diethyl phthalate, magnesium stearate, titanium dioxide, polydextrose, triacetin, Macrogol/PEG, gelatin, sodium lauryl sulphate, shellac, potassium hydroxide, black iron oxide, FD&C Blue #1(180 mg, 240 mg, 300 mg and 360 mg) and FD&C Yellow#6 (180 mg and 240 mg). It is soluble in water, methanol, and chloroform. The chemical structure is:ĭiltiazem hydrochloride, USP is a white to off-white crystalline powder with a bitter taste. Chemically, diltiazem hydrochloride is 1, 5-Benzothiazepin-4(5H)-one, 3-(acetyloxy)-5-2, 3-dihydro-2-(4-methoxyphenyl)-, monohydrochloride,(+)-cis. Diltiazem hydrochloride is a calcium ion cellular influx inhibitor (slow channel blocker or calcium antagonist).