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cardio:ccb:dhp

Dihydropyridine Calcium Channel Blockers

Dihydropyridine Calcium Channel Blockers (DHP CCBs) are potent arterial vasodilators that reduce systemic vascular resistance (SVR) by blocking L-type calcium channels in vascular smooth muscle.

They are primarily used for:

• Hypertension • Stable angina • Vasospastic (Prinzmetal) angina

DHP CCBs primarily affect blood vessels, not cardiac conduction.


Mechanism of Action

DHP CCBs:

• Block L-type calcium channels in vascular smooth muscle • Decrease intracellular calcium • Cause arteriolar vasodilation

Net Effects:

• ↓ Systemic vascular resistance (afterload) • ↓ Blood pressure • Mild reflex ↑ heart rate (possible)

Minimal direct effect on: • SA node • AV node • Cardiac contractility

Contrast with: • Non-Dihydropyridine Calcium Channel Blockers


Common DHP CCBs

Most outpatient hypertension management uses: → Amlodipine


Indications

Hypertension

  • • First-line therapy
  • • Effective in Black patients
  • • Often combined with ACE Inhibitors or ARBs

Hypertension Module


Stable Angina

• Reduce afterload • Improve myocardial oxygen supply-demand balance

Anti-Anginal Module


Vasospastic (Prinzmetal) Angina

• First-line therapy • Relieve coronary artery spasm


Hypertensive Emergency (IV agents)

Used for rapid BP control.


Adverse Effects

• Peripheral edema (dose-dependent) • Flushing • Headache • Reflex tachycardia (short-acting agents) • Gingival hyperplasia (rare)

Edema is due to preferential arteriolar dilation without venous dilation.

Adding a RAAS blocker may reduce edema.


Contraindications / Cautions

Use caution in:

  • • Severe hypotension
  • • Advanced aortic stenosis

Generally safe in:

• HFrEF (amlodipine acceptable)

Unlike:

Non-DHP CCBs which may worsen systolic HF.


DHP vs Non-DHP Summary

DHP CCBs:

  • • Vascular selective
  • • Strong BP reduction
  • • Minimal conduction effect

Non-DHP CCBs:

  • • Affect SA/AV node
  • • Reduce heart rate
  • • Used in arrhythmias

See: → Non-DHP Calcium Channel Blockers


Clinical Pearls

  • ✔ Potent arteriolar vasodilators
  • ✔ First-line for hypertension
  • ✔ Excellent in Black patients
  • ✔ Peripheral edema is common
  • ✔ Safe in HFrEF (amlodipine)
  • ✔ Do not use short-acting nifedipine in hypertensive emergencies

Related:

Calcium Channel Blockers OverviewHypertension ModuleAnti-Anginal ModuleReturn to Cardiovascular Modules

cardio/ccb/dhp.txt · Last modified: by andrew2393cns