Calcium channel blockers(CCBs) Considered as a different class of vasodilators that are used in treatment of angina and hypertension. Mechanism of action is based on the role of calcium in maintaining smooth muscle tone and in the contraction of myocardium.Blocking the entry of calcium through cell surface L-type channels relaxes smooth muscle cells.Selective blocks arteriole smooth muscle cells is most desirable for reduction of PVR. There are dihydropyridine CCBs and non-dihydropyridine CCBs in treating hypertension.These are alternative drugs for initial treatment of hypertension in patients who cannot take B-blockers (e.g.due to angina bronchospastic disease). Diphenylalkylamines-Verapamil,is less selective on the type of calcium channels and have effects on both arteriole and cardiac SMC. Benzothiazepines--Diltiazem,has similar function but less adverse effect than verapamil
Calcium channel blockers (CCBs) • Considered as a different class of vasodilators that are used in treatment of angina and hypertension. • Mechanism of action is based on the role of calcium in maintaining smooth muscle tone and in the contraction of myocardium. Blocking the entry of calcium through cell surface L-type channels relaxes smooth muscle cells. Selective blocks arteriole smooth muscle cells is most desirable for reduction of PVR. • There are dihydropyridine CCBs and non-dihydropyridine CCBs in treating hypertension. These are alternative drugs for initial treatment of hypertension in patients who cannot take -blockers (e.g. due to angina + bronchospastic disease). Diphenylalkylamines – Verapamil, is less selective on the type of calcium channels and have effects on both arteriole and cardiac SMC. Benzothiazepines -- Diltiazem, has similar function but less adverse effect than verapamil
Dihydropyridines-DHPCCBs are an expanding class of CCBs that include amlodipine,nifedipine,felodipine,isradipine,nicardipine,and nisoldipine. They have higher affinity for vascular calcium channels than for cardiac calcium channels. One of these DHPCCBs,amlodipine,is clinically used together with benazepril,an ACE inhibitor,under the commercial name of Lotrel. Amlodipine (Norvasc) Adverse effects and toxicity: Dizziness,headache and constipation are common. Verapamil should not be used in congestive heart failure patients due to its negative inotropic effect.Use with caution in patients with conductive disturbances involving SA or AV node
Adverse effects and toxicity: • Dizziness, headache and constipation are common. • Verapamil should not be used in congestive heart failure patients due to its negative inotropic effect. Use with caution in patients with conductive disturbances involving SA or AV node. Dihydropyridines – DHPCCBs are an expanding class of CCBs that include amlodipine, nifedipine, felodipine, isradipine, nicardipine, and nisoldipine. They have higher affinity for vascular calcium channels than for cardiac calcium channels. • One of these DHPCCBs, amlodipine, is clinically used together with benazepril, an ACE inhibitor, under the commercial name of Lotrel. Amlodipine (Norvasc)