Cardiac - Antiarrhythmics Flashcards
MOA of Adenosine
Slows conduction time through the AV node, interrupting the re-entry pathways through the AV node, restoring normal sinus rhythm.
Adenosine adult dosage
Peripheral IV: 6 mg, 12 mg, 12 mg
Central line: 3 mg, 6 mg, 6 mg
Adenosine indications
Conversion and termination of supraventricular tachycardias
Adenosine pharmacokinetics
Onset: Rapid
Duration: Brief
Half life: <10 seconds
Adenosine contraindications
Hypersensitivity
2nd or 3rd degree AV node block
Sick sinus syndrome without artificial pacemaker
Adenosine - how supplied
6 mg/2 ml ampoule
Atropine MOA
competitively antagonizes acetylcholine at muscarinic receptors, producing parasympatholytic and vagolytic effects
Atropine dosage
Bradycardia: 0.6 mg, repeat up to ~3 mg (Handbook)
1 mg, repeat up to 3 mg (UpToDate)
Organophosphate toxicity: 1-2 mg IM/IV, repeat till symptoms resolve
Atropine pharmacokinetics
Onset: <2 mins
Peak: 3 mins
Duration: 2-6 hours
Atropine contraindications
Tachycardia, narrow angle glaucoma, thyrotoxicosis, prostatic hypertrophy, myasthenia gravis
Atropine - how supplied
Preload 1 mg/10 mL
Labetalol MOA
competitively blocks adrenergic stimulation of beta1 receptors within the myocardium and beta2 receptors within bronchial and vascular smooth muscle and alpha1 receptors within vascular smooth muscle.
Labetalol adult bolus dosage
Start at 20 - 80 mg slow IV push
Additional doses can be given (20-80 mg) at 10 min intervals until desired supine B/P is achieved or total cumulative dose of 300 mg.
Goal is to reduce mean arterial B/P by no more than 25% in first hour, then aim for 160/100-110 mmHg.
Labetalol infusion dosing
0.5-2 mg/min. Adjust based on B/P response.
Max cumulative dose of 300 mg.
Labetalol pharmacokinetics
Onset (IV): within 5 mins
Peak (IV): 5-15 mins
Duration (IV): 16-18 hours