DHPCCBs

Dihydropyridine calcium channel blockers (DHP CCBs) are a subclass of calcium channel blockers that preferentially inhibit L-type calcium channels in vascular smooth muscle. By reducing calcium influx, they promote arterial dilation and lower systemic vascular resistance. Their effect is mainly vascular; at typical doses they have less direct influence on cardiac conduction and contractility compared with non-dihydropyridine CCBs such as verapamil and diltiazem.

Common agents include amlodipine, felodipine, nifedipine, nisoldipine, nicardipine, nimodipine, and clevidipine in intravenous form. Long-acting formulations are preferred for chronic hypertension to minimize reflex tachycardia and edema. Nimodipine is specialized for cerebral vasospasm after subarachnoid hemorrhage, while nicardipine and clevidipine are used for hypertensive emergencies.

Indications include hypertension, stable angina, vasospastic (Prinzmetal) angina, and, for certain agents, Raynaud phenomenon. Long-acting formulations are favored to reduce adverse effects such as edema and tachycardia. Some DHP CCBs have specialized roles (for example, nimodipine for cerebral vasospasm). In heart failure with reduced ejection fraction, DHP CCBs are not typically first-line; caution is advised with short-acting formulations due to risk of adverse hemodynamic effects.

Adverse effects and safety considerations include peripheral edema, headaches, flushing, palpitations, and gingival hyperplasia; reflex tachycardia and hypotension can occur. They are contraindicated in certain conditions such as severe aortic stenosis or cardiogenic shock. Many DHP CCBs are metabolized by hepatic CYP3A4, and their levels can be increased by inhibitors or decreased by inducers of this enzyme; drug interactions with grapefruit juice and other CYP3A4 modulators are possible.