Dihydropyridine and Non-Dihydropyridine Calcium Channel Blockers

Calcium channel blocker choice is a tissue-target decision. If the clinical problem is excessive arteriolar resistance, a long-acting dihydropyridine (DHP) lowers blood pressure mainly by relaxing vascular smooth muscle. If the goal is to slow AV-nodal conduction or reduce myocardial contractility, a non-dihydropyridine (non-DHP) such as verapamil or diltiazem may be useful—but only when ventricular function and conduction status make that negative cardiac effect tolerable. For Canadian hypertension practice, Hypertension Canada 2025 defines hypertension as blood pressure of 130/80 mm Hg or higher when measured with validated automated office measurement under standardized conditions. Pharmacotherapy generally starts at 140/90 mm Hg or higher, or at systolic pressure of 130–139 mm Hg when cardiovascular risk is high. When medication is indicated, initial therapy usually uses two first-line agents from different classes, preferably in a single-pill combination. A long-acting DHP can be one component; a non-DHP is not a first-line hypertension choice. ACE inhibitors and ARBs must never be combined.