In addition to being used as antianginal and antiarrhythmic agents, calcium channel blockers are used to treat weak and moderate hypertension. These drugs prevent calcium ions from entering into the smooth muscle cells of peripheral vessels, and they cause relaxation of peripheral vessels, which leads to lowering of arterial blood pressure. In clinically used doses, calcium channel blockers relax smooth musculature of arteries and have little effect on veins. In doses that relax smooth musculature, calcium channel blockers have relatively little effect on cardiac contractility.
In antihypertension therapy, the most frequently used drugs are diltiazem (19.3.10), verapamil (19.3.15), and nifedipin (19.3.16), which appear to be equally effective drugs for treating hypertension. Methods of syntheses have already been discussed in Chapter 19.
Diltiazem (19.3.10): The synthesis of this drug is described in Chapter 19.
Diltiazem reduces transmembrane influx of calcium ions into cardiac muscle cells and vascular smooth musculature. It causes widening of coronary and peripheral vessels. It increases coronary blood flow, thus, preventing the development of coronary artery spasms. It lowers elevated blood pressure and reduces tachycardia.
Verapamil (19.3.15): The synthesis of this drug is described in Chapter 19.
Verapamil possesses antiarrhythmic, antianginal, and hypotensive activity. It reduces the myocardial need for oxygen by reducing contractility of the myocardium and slowing the frequency of cardiac contractions. It causes dilation of coronary arteries and increased coronary blood flow. It reduces tonicity of smooth musculature, peripheral arteries, and overall peripheral vascular resistance. It provides antiarrhythmic action in supraventricular arrhythmia.
Verapamil is used to prevent attacks of stenocardia, arterial hypertension, and to treat and prevent supraventricular arrhythmia.
19.3.10 ch2 ch2
Was this article helpful?
Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...