From the Guidelines
Seek immediate medical attention by calling 911 or going to the emergency room if you've taken a double dose of digoxin and are experiencing shortness of breath and fatigue. These symptoms could indicate digoxin toxicity, which is a serious medical emergency, as noted in the 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1. Digoxin has a narrow therapeutic window, meaning the difference between an effective dose and a toxic dose is small. Taking a double dose can lead to dangerous levels in your bloodstream. Symptoms of toxicity include shortness of breath, fatigue, nausea, vomiting, visual disturbances, and irregular heartbeat. Some key points to consider in the management of digoxin toxicity include:
- Discontinuing the medication, monitoring rhythm, and maintaining normal serum potassium may be sufficient in mild cases, as stated in the 2017 AHA/ACC/HRS guideline 1.
- Intravenous magnesium is often administered if ventricular arrhythmias are present, and temporary pacing may be needed for atrioventricular block or asystole 1.
- For more severe intoxication, the treatment of choice is digoxin-specific Fab antibody, which has been shown to have a rapid response and improve survival in severely intoxicated patients 1. Do not take any additional doses until you've been evaluated by a healthcare provider. When you reach medical care, inform them exactly what happened, including the timing of the missed dose, when you took the double dose, and when your symptoms began. They will likely check your digoxin blood levels and may perform an ECG to assess your heart rhythm. In the future, if you miss a dose of digoxin, take it as soon as you remember unless it's almost time for your next dose, in which case skip the missed dose and resume your regular schedule. Never double up on this medication.
From the FDA Drug Label
OVERDOSAGE Digoxin should be temporarily discontinued until the adverse reaction resolves. Treatment of Adverse Reactions Produced by Overdosage: Withdrawal of digoxin may be all that is required to treat the adverse reaction.
The patient should stop taking digoxin immediately and seek medical attention due to experiencing shortness of breath and fatigue after missing a dose and then taking a double dose.
- The patient's symptoms may be indicative of digoxin toxicity, which can be life-threatening.
- Medical professionals should assess the patient's condition and consider the administration of DIGIBIND [Digoxin Immune Fab (Ovine)] if necessary, as well as correction of any electrolyte disturbances 2.
From the Research
Missed Dose and Double Dosing of Digoxin
- If a patient misses a dose of digoxin and then takes a double dose, they may experience symptoms of digoxin toxicity, such as shortness of breath (dyspnea) and fatigue 3, 4.
- Digoxin toxicity can occur even when the serum digoxin concentration is within the therapeutic range, and it can trigger fatal arrhythmias 4.
Treatment of Digoxin Toxicity
- Digoxin-specific antibody fragments (Fab) are a safe and effective treatment for digoxin toxicity, especially in severe cases 3, 4, 5.
- The dose of digoxin-Fab required depends on the amount ingested and the serum digoxin concentration, but these are not essential for determining the dose 4.
- In acute poisoning, a small bolus of 80 mg of digoxin-Fab, repeated if necessary, titrated against clinical effect, is likely to achieve equivalent benefits with much lower total doses 3.
- In chronic poisoning, it may be simplest to give 40 mg (1 vial) of digoxin-Fab at a time and repeat after 60 min if there is no response 3.
Management of Digoxin Toxicity
- Monitoring should continue after treatment with digoxin-Fab because of the small risk of rebound toxicity 4.
- Restarting digoxin therapy should take into account the indication for digoxin and any reasons why the concentration became toxic 4.
- Expert consensus recommends considering the time of ingestion and nature of the exposure (ie, acute, acute-on-chronic, chronic) and the use of digoxin immune Fab for life-threatening exposure to decrease the risk of death 6.