Calcium Channel Blockers
- Goldfarb School of Nursing
- Nursing Pharmacology
- Calcium Channel Blockers
Last Modified: 2012-07-16
Related Textbooks:Pharmacology and the Nursing Process
Slow Channel Blockers
Ca+ channels regulate vascular smooth muscle contraction in bl vessels & the heart electrical system.
SA node - regulates pacemaker activity (↑ ♥ rate)
AV node - coordinates contraction of ventricles w contraction of atria (conduction accelerates)
SA node - slows ♥ rate
AV node - suppresses conduction through the AV node
- Peripheral arterioles (NOT veins)
- Arteries & arterioles of ♥ (NOT veins)
- Myocardium of ♥
- SA Node
- AV Node
Distribution: highly bound protein
Metabolism: liver - undergoes 1st pass effect (loses powerfulness)
- Dihydropyridines (LGST Grp) - works on arterioles only. Used for Hypertension only
- Non-dihydropyridines - arterioles & heart. Used for Hypertension & Heart
**Amlodipine (Norvasc) - oral
Clevidipine (Cleviprex) - IV ONLY
**Felodipine (Plendil) - oral
Nisoldipine (Sular), Nimodipine (Nimotop), Nicardipine (Cardene)-oral
- Angina (not acute - CCBs will ↓ # of angina events over time)
- NOT CARDIAC DYSRHYTHMIAS!!! Produces very little blockade of Ca+ channels in the ♥
*Peripheral edema *Exacerbation of Angina (1st start & Temp)
*Dizziness *Reflex Tachycardia
Beta blockers combined w nondihydropyridines intensify their adverse effects!
- Severe LV dysfunction
- 2nd & 3rd heart block
- Severe heart failure
- Severe hypotension
Excessive doses of Nifedipine loses selectivity & affects heart as well
Diltiazem (Cardizen, Dilacor)
- Oral - Don't crush SR. Prior to admin take BP & pulse (hypo or brady, call prescriber B4 admin)
- IV - Inject slowly (over 2-3 min). Monitor ECG-facilities for cardioversion/pacing avail
- Cardiac Dysrhythmias
- Migraine (stabilize vasculature prophylactically)
**The direct effects are counterbalanced by indirect effects so the drugs have very little effect on cardiac performance.
- Beta Blockers - When given IV, dose several hours apart b/c both can slow HR.
- Digoxin - ↑ plasma levels of digoxin can occur. If signs of toxicity reduce digoxin dosage.
Blockade of Ca+ channels in smooth muscles of the intestines.
Edema of Feet & Ankles
SA node blockade = bradycardia
AV node blockade = partial or complete AV block
Heart Healthy = Little clinical significance
Not Heart Healthy = Seriously exacerbate dysfunction
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