Amiodarone
Mechanism of Action:
Inhibits adrenergic stimulation; affects Na, K, Ca channels; prolongs action potential and refractory period in myocardial tissue. Decreases AV conduction and sinus node function.
Indications:
Management of life-threatening recurrent ventricular fibrillation, (VF) or recurrent hemodynamically unstable ventricular tachycardia (VT) unresponsive to other therapy.
1.Paroxysmal SVT
2.Nodal and ventricular Tachycardias
3.Atrial fibrillation and flutter
4.VF
5.Tachyarrhythmias associated with Wolff-Parkinson – White Syndrome
| Amiodarone |
| Availability: Infusion (Pre-Mix): 150 mg/100 mL; 360 mg/200 mL. Injection, Solution: 50 mg/mL, 3 mL, 9 mL, 18 mL. Tablets: 100 mg, 200 mg, 400 mg |
| Administration/handling: IV Reconstitution • Infusions longer than 2 hrs must be administered/diluted in glass or polyolefin bottles. • Dilute loading dose (150 mg) in 100 mL D5W (1.5 mg/mL). • Dilute maintenance dose (900 mg) in 500 mL D5W (1.8 mg/ mL). Concentrations greater than 3 mg/ mL cause peripheral vein phlebitis. Rate of administration • Does not need protection from light during administration. • Administer through central venous catheter (CVC) if possible, using in-line filter. • Bolus over 10 min (15 mg/min) not to exceed 30 mg/min; then 1 mg/min over 6 hrs; then 0.5 mg/min over 18 hrs. • Infusions longer than 1 hr, concentration not to exceed 2 mg/mL unless CVC used. PO • Give consistently with regard to meals to reduce GI distress. • Tablets may be crushed. • Do not give with grapefruit products. |
| Ventricular Arrhythmias : PO: Adults, elderly: Initially, 400 mg q8–12h for 1–2 wks, then decrease to 200–400 mg once daily. Maintenance: 200–400 mg/day. |
| IV infusion: Adults, elderly: Initially, 150 mg over 10 min, then 1 mg/min over 6 hrs; then 0.5 mg/min. Continue this rate over at least 18 hrs or until complete transition or oral. Breakthrough stable VT: 150 mg in 100 mL D5W or NS over 10 min. 1–6 mg/mL. |
| Use with caution in hepatic impairment |
| Storage: Store at room temperature. • Stable for 24 hrs when diluted in glass or polyolefin containers; stable for 2 hrs when diluted in PVC containers. |
Cautions & Contraindications:
- Hypersensitivity
- Bradycardia induced syncope (except in the presence of a pacemaker)
- Second- and third-degree AV block (except in the presence of a pacemaker)
- Severe sinus node dysfunction; causing marked sinus bradycardia
- Cardiogenic shock
Side – Effects:
- Photosensitive rash
- Slate- grey skin discoloration
- Bradycardia
- Hypothyroidism or hyperthyroidism
- Corneal Microdeposits (dazzling at night)
- Pulmonary fibrosis/ pneumonitis
- Hypotension
- Constipation
- Headache
- Bitter or metallic taste
Metabolism & Half – Life:
Slowly, variably absorbed from GI tract. Protein binding: 96%. Extensively metabolized in liver. Excreted via bile; not removed by haemodialysis. Half-life: 26–107 days; metabolite: 61 days.
Drug Interactions:
- Increases plasma levels of warfarin, digoxin and phenytoin (reduce doses accordingly) leading to toxicity.
- Drugs that prolong QT interval
- May cause changes in ECG, thyroid function test results Grapefruit products may alter effect
NURSING CONSIDERATIONS
BASELINE ASSESSMENT
1. Obtain baseline serum ALT, AST, alkaline phosphatase, ECG; pulmonary function tests, CXR in pts with pulmonary disease.
2.Assess B/P, apical pulse immediately before drug is administered (if pulse is 60/min or less or systolic B/P is less than 90 mm Hg, withhold medication, contact physician)
INTERVENTION/EVALUATION
1.Monitor for symptoms of pulmonary toxicity (progressively worsening dyspnea, cough). Dosage should be discontinued or reduced if toxicity occurs.
2.Assess pulse for quality, rhythm, bradycardia. Monitor ECG for cardiac changes (e.g., widening of QRS, prolongation of PR and QT intervals). Notify physician of any significant interval changes.
3.Assess for nausea, fatigue, paresthesia, tremor.
4.Monitor serum ALT, AST, alkaline phosphatase for evidence of hepatic toxicity.
5.Assess skin, cornea for bluish discoloration in pts who have been on drug therapy longer than 2 months.
6.Monitor thyroid function test results. If elevated hepatic enzymes occur, dosage reduction or discontinuation is necessary. Monitor for therapeutic serum level (0.5–2.5 mcg/mL). Toxic serum level not established.
PATIENT/FAMILY TEACHING
- Protect against photosensitivity reaction on skin exposed to sunlight.
- Bluish skin discoloration gradually disappears when drug is discontinued.
- Report shortness of breath, cough.
- Outpatients should monitor pulse before taking medication.
- Do not abruptly discontinue medication.
- Compliance with therapy regimen is essential to control arrhythmias.
- Restrict salt, alcohol intake.
- Avoid grapefruit products.
- Recommend ophthalmic exams every 6 months.
- Report any vision changes, signs/symptoms of cardiac arrhythmias.
Important Points:
1.Should only be initiated under specialist supervision.
2.ECG monitoring required when given Intravenously.
3.Should be administered through a central line or large IV cannula.
4.Can cause torsades de pointes, particularly in individuals with prolonged QT interval (congenital or acquired)
REFERENCES
- Robert Kizior, Keith Hodgson, Saunders Nursing Drug handbook,1st edition 2024, Elsevier Publications. ISBN-9780443116070
- McGraw Hill- Drug Handbook, Seventh Edition, 2013, McGraw Hill Education Publications,9780071799430.
- April Hazard, Cynthia Sanoski, Davi’s Drug Guide for Nurses -Sixteenth Edition 2019, FA Davis Company Publications,9780803669451.
- Jones and Bartlet, Pharmacology for Nurses, Second Edition, 2020, Jones and Bartlet Learning Publications, ISBN 9781284141986.
- Nursebro.com, Search – Nursebro
Stories are the threads that bind us; through them, we understand each other, grow, and heal.
JOHN NOORD
Connect with “Nurses Lab Editorial Team”
I hope you found this information helpful. Do you have any questions or comments? Kindly write in comments section. Subscribe the Blog with your email so you can stay updated on upcoming events and the latest articles.
