Cardiology · USMLE Step 1 and Step 2

Calcium Channel Blockers - Dihydropyridines song

Dihydropyridine CCBs - Uses & Overdose, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Calcium Channel Blockers - Dihydropyridines

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Key points in this song10

Dihydropyridines (e.g., amlodipine, nifedipine, nicardipine) selectively block L-type calcium channels in vascular smooth muscle, causing vasodilation with minimal direct cardiac effect at therapeutic doses.
The hallmark side effect is reflex tachycardia due to peripheral vasodilation and baroreceptor-mediated sympathetic activation, distinguishing them from non-dihydropyridines.
Amlodipine is first-line for hypertension and stable angina, particularly in patients with asthma or diabetes where beta-blockers are less preferred.
Nifedipine (short-acting) is associated with increased cardiovascular events due to rapid vasodilation and reflex sympathetic activation; only long-acting formulations are used for chronic therapy.
Dihydropyridines are the drug of choice for Prinzmetal (vasospastic) angina, relieving coronary artery spasm via smooth muscle relaxation.
Nicardipine and clevidipine are IV dihydropyridines used for hypertensive emergencies, especially in perioperative or neurological settings.
Classic adverse effects include peripheral edema (from precapillary dilation without postcapillary compensation), flushing, and headache.
Dihydropyridines are safe in heart failure with reduced ejection fraction only for amlodipine and felodipine; other dihydropyridines can worsen outcomes due to neurohormonal activation.
Nifedipine is used as a tocolytic to inhibit uterine smooth muscle contractions in preterm labor.
Overdose treatment includes IV calcium gluconate, high-dose insulin-glucose therapy, and vasopressors; lipid emulsion therapy may be used in refractory cases.