Pharm 101: Nifedipine

Class

Dihydropyridine Calcium Channel Blocker


Pharmacodynamics
  • Blocks vascular L-type calcium channels > cardiac channels:
    • Blocks activated and inactivated L-type calcium channels (alpha-1 subunit)
    • Resultant decreased transmembrane calcium current results in long-lasting relaxation in smooth muscle
    • Note verapamil causes a nonselective block of L-type calcium channel in vessels and heart
  • Dihydropyridines blocks smooth muscle calcium channels at concentrations below those required for significant cardiac effects
  • No effect on AV conduction

Pharmacokinetics
  • Slow-release formulation
  • High first pass metabolism, bioavailability 45-70%
  • High plasma protein binding
  • Extensive metabolism
  • Half-life 4 hours

Clinical uses
  • Hypertension
  • Raynaud’s phenomenon

Adverse effects
  • Hypotension, dizziness
  • Flushing
  • Nausea, constipation
  • Peripheral edema

Precautions/contraindications
  • Immediate-acting preparation may increased risk of MI in patients with hypertension

Other Dihydropyridines
  • Nimodipine has as high affinity for cerebral blood vessels and reduces morbidity after SAH
  • Amlodipine has a slower onset, longer half-life (30-50 hours) and longer duration of action than nifedipine

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MBBS (UWA) CCPU Emergency Medicine Advanced Trainee based in Melbourne, Australia. Co-author of the LITFL ECG Library. Likes Ultrasound, Echo, ECGs, and anything and everything with caffeine. Part of the 2021 ANZCEN Clinician Educator Incubator Programme | @rob_buttner | ECG Library |

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