What is the onset of action of digoxin (digitalis glycoside) in treating atrial flutter?

From the Guidelines

Digoxin takes at least 60 minutes to start working in atrial flutter, with peak effects developing up to 6 hours after administration. This is based on the findings of a 2011 study published in Circulation, which reported that intravenous digoxin has a delayed onset of action, typically taking at least 60 minutes to slow the ventricular response to atrial fibrillation, and up to 6 hours to reach its peak effect 1.

Key Points to Consider

• The efficacy of digoxin is reduced in states of high sympathetic tone, which can be a precipitant of paroxysmal atrial flutter 1.
• Digoxin is not effective in converting atrial flutter to sinus rhythm and may even perpetuate the condition 1.
• The use of digoxin is generally reserved for patients with heart failure or left ventricular dysfunction, or those who are sedentary and do not require rate control during activity 1.

Clinical Implications

• For acute management of atrial flutter, alternative agents may be preferred due to their faster onset of action and greater efficacy 1.
• When using digoxin, it is essential to monitor for signs of toxicity, such as nausea, visual disturbances, confusion, and arrhythmias, and to check serum potassium levels to minimize the risk of toxicity.
• Combination therapy with beta-blockers or calcium channel blockers may be necessary to achieve optimal rate control in atrial flutter.

From the FDA Drug Label

The times to onset of pharmacologic effect and to peak effect of preparations of digoxin are shown in Table 2:

• Documented for ventricular response rate in atrial fibrillation, inotropic effects and electrocardiographic changes. ProductTime to Onset of Effect *Time to Peak Effect † Digoxin Tablets 0. 5 - 2 hours 2 - 6 hours Digoxin Elixir Pediatric 0.5 - 2 hours 2 - 6 hours Digoxin Solution in Capsules 0. 5 - 2 hours 2 - 6 hours Digoxin Injection/IV 5 - 30 minutes † 1 - 4 hours

The time to onset of effect of digoxin for atrial fibrillation (which is similar to atrial flutter) is 0.5 - 2 hours for oral preparations and 5 - 30 minutes for intravenous administration. The time to peak effect is 2 - 6 hours for oral preparations and 1 - 4 hours for intravenous administration 2.

Key points:

• Time to onset of effect: 0.5 - 2 hours (oral), 5 - 30 minutes (IV)
• Time to peak effect: 2 - 6 hours (oral), 1 - 4 hours (IV)

From the Research

Time to Effectiveness of Digoxin in Atrial Flutter

• The time it takes for digoxin to work in atrial flutter can vary, but according to a study published in 1993 3, the median time to ventricular rate control was 11.6 hours from the first dose of digoxin.
• Another study from 2018 4 found that digoxin was superior to placebo in reducing heart rate within 6 hours of treatment onset, with a mean difference of -12.0 beats per minute.
• A 2024 study 5 found that a target heart rate < 110 beats per minute within 24 hours from digoxin loading dose was achieved in 60% of the cohort.

Factors Affecting Digoxin Efficacy

• The efficacy of digoxin can be influenced by various factors, including the dose and serum concentration of digoxin, as well as the presence of other medical conditions or concomitant therapies 5, 6.
• A study from 2004 7 noted that the addition of digoxin to the regimen can cause a favorable outcome, but digoxin as a single agent is generally less effective in slowing the ventricular rate in acute settings.
• The choice of treatment, including digoxin, should be individualized depending on the clinical situation, taking into account factors such as myocardial ischemia, myocardial infarction, and hyperthyroidism 7.