17-09-2012, 11:05 AM
Calcium Channel Blockers and Anti Hypertensive Drugs
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INTRODUCTION
•A calcium channel blocker (CCB) is a chemical that disrupts the movement of calcium through calcium channel.
•CCB Drugs devised to target neurons are used as Anti epileptics.
•Clinical usage of CCB is to decrease Blood Pressure in patients with hypertension.
•Used to reduce chest pain.
•CCBs have high mortality rates over extended periods of use.
CCBs – Mechanisms of Action
•Increase the time that Ca2+ channels are closed.
•Relaxation of the arterial smooth muscle but not much effect on venous smooth muscle
•Significant reduction in after load but not preload
ADVANTAGES OF CCBs :
1.Do not compromise haemodynamics; no impairment of physical work capacity.
2.No sedation or other CNS effect.
3.Not contraindicated in asthma.
4.Do not impair renal perfusion.
5.Do not affect male sexual function.
Concerns in the use of CCBs as Anti Hypertensive Drugs
•The negative inotropic/dromotropic action of Verapamil/ditiazem may worsen CHF.
•DHP are less likely to do so.
•Nifedipine decreases insulin release, so diabetes may occur.
•CCBs specially Nifedipine may emphasize bladder voiding difficulty in elderly males .