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Case Reports
. 2023 Sep 30;15(9):e46282.
doi: 10.7759/cureus.46282. eCollection 2023 Sep.

Reassessing the Safety of Pill-in-the-Pocket Propafenone

Andrew G Kim  1 , Majid Yavari  2 , Rand Sabanci  1 , Esosa Ukponmwan  1 , Fatima Ali-Ahmed  3
Affiliations
Case Reports

Reassessing the Safety of Pill-in-the-Pocket Propafenone

Andrew G Kim et al. Cureus. .

Abstract

The current guidelines state that propafenone can be used in combination with a beta-blocker or a calcium channel blocker for pharmacologic cardioversion of recent-onset atrial fibrillation in patients without structural heart disease. To prevent the conversion from atrial fibrillation to atrial flutter with a rapid ventricular rate, it is recommended to administer propafenone following the administration of a beta-blocker or a calcium channel blocker. However, this combination carries the potential risk of cardiogenic shock. There are several scenarios where this combination can lead to shock, attributed to the variable pharmacokinetics of propafenone among individuals and its significant drug interactions with commonly used AV nodal blockers, such as metoprolol and diltiazem. Additionally, a significant proportion of the population has genetic polymorphisms that affect the metabolism of these medications. While pill-in-the-pocket propafenone is also employed in outpatient settings, unexpected severe and life-threatening reactions have been reported. In this context, we present a case report of severe propafenone toxicity in a closely monitored inpatient setting aimed at converting atrial fibrillation.

Keywords: antiarrhythmic; atrial fibrillation; atrial flutter; cardioversion; propafenone.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. The chest X-ray upon arrival at the emergency department.
Figure 2
Figure 2. The initial ECG showing atrial fibrillation with a ventricular rate of 149 bpm.
Figure 3
Figure 3. The ECG taken about two hours after the administration of propafenone showing atrial fibrillation with a ventricular rate of 41 bpm.
Figure 4
Figure 4. The ECG on the following day showing atrial flutter with a ventricular rate of 137 bpm.
Figure 5
Figure 5. The ECG on discharge showing atrial flutter with a predominant 4:1 AV block at a ventricular rate of 83 bpm.
Figure 6
Figure 6. Metabolic pathway of propafenone.
Propafenone is metabolized by cytochrome P450 enzymes, mainly 2D6 and 3A4 [11].
See this image and copyright information in PMC

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