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 (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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