Hey everyone!
I was reading about calcium channel blockers for vasospastic angina and it was a good refresher to know that even though they belong to the same class, they act by different mechanisms.
Dihydropyridines block slow calcium channels.
They vasodilate coronary arteries, reduce coronary resistance, increase coronary blood flow, and may enhance the development of coronary collaterals.
The vasodilatation and increase in coronary artery blood flow result from the blockade of calcium influx as well as an increase the levels of nitric oxide and bradykinin.
They can cause reflex tachycardia.
Verapamil has different physiologic effects from the dihydropyridines because of a different interaction with the calcium channels.
Verapamil is effective in angina because it decreases myocardial oxygen demand by acting as a negative inotrope and chronotrope and by lowering the systemic blood pressure.
Changes in contractility are minimal in patients without heart disease; however, verapamil can exacerbate heart failure in patients with cardiac dysfunction due to its negative inotropic activity.
Diltiazem is a potent coronary but a mild arterial vasodilator, producing improved blood flow through coronary epicardial vessels, collaterals, and normal and ischemic myocardium, as well as lowering mean arterial pressure.
That's all!
-IkaN
I was reading about calcium channel blockers for vasospastic angina and it was a good refresher to know that even though they belong to the same class, they act by different mechanisms.
Dihydropyridines block slow calcium channels.
They vasodilate coronary arteries, reduce coronary resistance, increase coronary blood flow, and may enhance the development of coronary collaterals.
The vasodilatation and increase in coronary artery blood flow result from the blockade of calcium influx as well as an increase the levels of nitric oxide and bradykinin.
They can cause reflex tachycardia.
Verapamil has different physiologic effects from the dihydropyridines because of a different interaction with the calcium channels.
Verapamil is effective in angina because it decreases myocardial oxygen demand by acting as a negative inotrope and chronotrope and by lowering the systemic blood pressure.
Changes in contractility are minimal in patients without heart disease; however, verapamil can exacerbate heart failure in patients with cardiac dysfunction due to its negative inotropic activity.
Diltiazem is a potent coronary but a mild arterial vasodilator, producing improved blood flow through coronary epicardial vessels, collaterals, and normal and ischemic myocardium, as well as lowering mean arterial pressure.
That's all!
-IkaN
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