University of Minnesota wordmark College of Pharmacy logo
Courses Phar 6122

 

ekgcircle3.gif (1164 bytes) Lecture Outlines: Diseases/Syndromes
Arrhythmias
Supraventricular Arrythmias Lecture:
Learning Objectives and Outline
General Treatment Issues
The Use of CCBA's for Afib/Aflutter
Digoxin for Afib/Aflutter
Beta-Blockers for Afib/Aflutter
Ibutilide Fumarate (Corvert®)
General Issues with Drug Selection
Management of Supraventricular Arrhythmias
Cardiac Conduction System Lecture
Antiarrhythmic Drug Tables
Ventricular Arrythmia Management Lecture

 

SUPRAVENTRICULAR ARRYTHMIAS LECTURE

Digoxin for Afib/Aflutter

Digoxin for Afib/Aflutter:
  • Often ineffective and slow in onset of action
  • Slowed VRR can be expected after one hour but maximal effect only after 24-48 hours
  • May be superior choice for long term care of patients with systolic dysfunction (CHF)
  • Often ineffective if exercise-related increases in VRR occur

Digoxin for SVT:

  • Often used to control VRR in AF by enhancing vagal effects on the AV node
  • Limitations are in situations with vagal tone is low (exercise, thyrotoxicosis, hyperadrenergic states) or when a rapid response is desired. Several studies demonstrated chronic dig therapy alone is no better than placebo in controlling VRR during AF paroxysms
  • May be superior choice for long term care of patients with systolic dysfunction (CHF)
Dosing Digoxin:
  • LD: 10-15 mcg/kg (LBW*)
  • MD: (14 + ClCr/5) % x LD
  • Give LD 1/2 now then remainder of load as 1/4 x 2 separated by at least 6-8 hours
  • Monitor: HR, BP, EKG, K+, Ca++
  • Question need for LD in CHF
  • Reduce load and MD in renal impairment
  • V. rate is not a good measure of chronotropic effect of digoxin

*Many drugs are dosed by using lean body weight. Calculation of lean body weight (LBW) is as follows:

- LBW male = 50 + (2.3 x + # of inches > 5 ft)
- LBW female = 45 + (2.3 x # of inches > 5 ft)

Digoxin Toxicities:
  • Poorly correlated with digoxin concentrations
  • Therapeutic window 0.5-2ng/mL
  • DILS (dig. immunoreactive like substance) may cause major interferrence with interpreting normal digoxin levels in select patient populations:

  • - pregnant patients
    - patients with chronic and possibly acute renal failure
    - neonates

  • Systemic toxicities
  • Anorexia, N, V, diarrhea, yellow-green or blurred vision
  • Cardiac toxicities:

  • - Heart block (2° or 3°)
    - Ventricular ectopy
    - PAT with 2° AV block

 

 

[Phar 6122 Homepage] [College of Pharmacy Homepage] [University of Minnesota Homepage]

 

The University of Minnesota is an equal opportunity educator and employer.

The views and opinions expressed in this page are strictly those of the page author. The contents of this page have not been reviewed or approved by the University of Minnesota.

©1997 by the Regents of the University of Minnesota
Last updated: 07/31/2009

Course Director: Robert J. Straka
Maintained by: Webmaster