Meds For Dysrhythmias

Question 1

Types of meds

Answer 1

Class I: Sodium channel blockers
- inhibit sodium ion movement
- Ia prolong duration of electrical stimulation
- Ib shorten duration of electrical stimulation
- potent myocardial depressants, slow conduction rate
Class II: Beta adrenergic antagonists
Class III: Potassium channel blockers
Class IV: Calcium channel blockers

Question 2

Lidocaine

Answer 2

Sodium channel blocker
MOA: mild blockage of entry of sodium into myocardium, slows conduction and shortens refractory period to suppress dysrythmia

SE: DC if toxicity (slurred speech, parasthesia, restlessness, confusion, drowsiness, convulsions)
- Sam’s (slurred speech, altered CNS, muscle twitch, seizures)

Dose: IV Pump, incompatible wit phenytonin, beta blockers, procainamide

Nurse: monitor cardiac, kidney, lungs and watch for CNS side effects

Question 3

Propranolol

Answer 3

Beta blocker

MOA: blockage of cardiac B1 receptors, Dec SA node and contractility, slows HR

SE: bradycardia, hypotension, syncope, CHF, rebound angina. Use cautiously with COPD/asthma

Consider: hold of HR <60, take with glass of water, do not stop abruptly, dont take with aluminum antiacid

Question 4

Amiodarone (cordarone)

Answer 4

Potassium channel blocker

MOA: blocks potassium channels, prolongs action potential, Dec cardiac workload

Usage: PO or IV for life threatening Vfib

SE: GI upset, dizzy, fatigue, bradycardia, hypotension, photosensitivity, cardiac arrest, blindness, CNS effects , tremors, hallucinations
- FDA requires drug guide

Box: hepatotoxicity and pulmonary toxicity

Nursing: report GI symptoms, baseline chest x-ray and pulmonary function test, monitor vision changes, ECG, K levels, lung sounds, dont give if bradycardia, monitor liver function

Question 5

Diltiazem (cardizem)
Verapamil (calan)

Answer 5

Calcium channel blocker

MOA: relaxes muscle of heart and blood vessels. Inhibit influx of calcium ions during depolarization, slows conduction velocity

Use: tachycardia, atrial flutter, angina, HTN

SE: peripheral edema, nausea, constipation, headache, drowsiness, fatigue, hypotension, CHF

Nursing: monitor BP and HR, ECG, limit alc and caffeine, may elevate AST, ALT, LDH, CPK, and Alk Phos.

Question 6

Atropine

Answer 6

Anticholinergic; muscadine receptor blocker
First choice for bradycardia

MOA: blocks parasympathetic stimulus, adrenergic system take over
Inhibits action of acetylcholine

SE: tachycardia, palpitations, congestion, dry mouth, hot skin, blurred vision, photophobia, N/V, constipation, abd distention, urinary retention

Overdose: hot as a hare (inc temp) , mad as a hatter(delirium), red as a beet(flushed face), dry as a bone (Dec secretions, thirsty)

Question 7

Digoxin (lanoxin)

Answer 7

Cardiac glycoside

MOA: inhibits sodium potassium, inc Ca intracellular, inc contractility, Dec conduction through AV node, Dec HR,

SE: GI symptoms, headache, blurred vision, toxicity: narrow therapeutic range, vision changes, heart block, HYPOKALEMIA!!

Dose: PO or IV, may. Be crushed, IV give loading dose, check dig levels constantly

Antidote: digibind

Contraindicated: Vfib, tachycardia unless HF, digoxin toxicity