Dihydropyridine Calcium Channel Blocker

Aka: Dihydropyridine Calcium Channel Blocker, Dihydropyridine

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II. Indications

  1. Hypertension

III. Contraindications

  1. Consider avoiding in Diabetes Mellitus (relative contraindication)
    1. May increase Proteinuria
  2. NOT contraindicated in combination with Beta Blockers
    1. Contrast with Non-Dihydropyridine Calcium Channel Blockers (Diltiazem, Verapamil) which slow AV nodal conduction

IV. Mechanism

  1. Nifedipine (Procardia) is prototype for class
  2. Dihydropyridine Calcium Channel Blockers
    1. Dihydropyridines are primarily active at vascular Smooth Muscle
    2. Contrast with Non-Dihydropyridines which are also active at cardiac Smooth Muscle

V. Medications: Oral

  1. Amlodipine (Norvasc)
    1. Dosing
      1. Typical dose: 5 mg orally daily (may start at 2.5 mg daily in elderly)
      2. Maximum: 10 mg orally daily (little benefit over 5 mg, but increased edema)
    2. Advantages
      1. Preferred first line oral antihypertensive Calcium Channel Blocker
      2. Long acting and less reflex Tachycardia than other Dihydropyridines, with improved cardiovascular outcomes
      3. Does not exacerbate Left Ventricular Dysfunction
  2. Nifedipine (Procardia)
    1. Consider in Hypertension control in pregnancy (long safety record)
  3. Felodipine (Plendil)
  4. Isradipine (Dynacirc)
  5. Nimodipine (Nymalize)
  6. Nisoldipine (Sular)

VI. Medications: Parenteral (Hypertensive Emergency)

  1. Background
    1. Counter Cerebral Vessel spasm (e.g. early Subarachnoid Hemorrhage, CVA)
  2. Clevidipine (Cleviprex)
  3. Nicardipine

VII. Adverse Effects

  1. See Calcium Channel Blocker
  2. Peripheral Edema (esp. Amlodipine)
    1. Occurs more commonly in women
    2. Occurs more commonly on Norvasc doses >5 mg
    3. Adding ACE Inhibitor to regimen decreases edema
    4. Avoid Diuretics to reduce Dihydropyridine -induced edema
      1. Dihydropyridine-induced edema mechanism is vasodilation fluid leak into interstitium, NOT Sodium and water retention

VIII. Drug Interactions

  1. Clarithromycin
    1. Increases Calcium Channel Blocker levels via CYP3A4 inhibition especially with Dihydropyridines and over age 65 years
      1. Provokes Hypotension and Bradycardia
      2. Risk of Acute Kidney Injury (often requiring hospitalization)
    2. References
      1. Gandhi (2013) JAMA 310(23):2544-53 [PubMed]

IX. References

  1. (2022) Presc Lett 29(11): 64-5

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