The event you described can happen, and it’s a known risk with pill-in-the-pocket AFib protocols, especially when metoprolol and flecainide are combined.

Both drugs slow heart rate and conduction. When flecainide converts AFib back to sinus rhythm, the beta-blocker effect can suddenly become unmasked, causing an abrupt drop in heart rate and blood pressure. Repeating metoprolol doses increases this risk.

Even if the protocol worked many times before, tolerance can change due to dehydration, illness, age, lower baseline BP/HR, or timing of conversion. The same doses can suddenly cause bradycardia, hypotension, and near-syncope, often landing people in the ER for observation — then resolving once the meds wear off.

Bottom line: pill-in-the-pocket isn’t “set and forget.” A hypotensive or near-fainting episode usually means the protocol needs re-evaluation or dose adjustment.

Sources:
• NEJM – Pill-in-the-Pocket AFib (Alboni et al.)
• PubMed review: adverse events with PITP (2022)
• FDA Flecainide Prescribing Information
• FDA Metoprolol Prescribing Information