Missed my metoprolol pill (25mg) at noon. After supper (~6:30 p.m.) I noticed the AF flutter and irregular heartbeat, reminding me of the oversight.  So I took a 25 mg metoprolol right away. It is now 10 p.m. There has been improvement in the degree of irregularity but the beats are not the normal even pace. What should I do? I am not experiencing any pain or shortness of breath.  I am 73. I normally take one 25mg tablet, twice a day (noon and before bedtime).
Hello. Thank you for your question. If this was a paroxysmal episode of atrial flutter, then there is only a slight chance that missing of a single dose of metoprolol causes it. This episode warrants treatment aiming converting this arrhythmia to sinus rhythm. The efforts in doing that should be undertaken in a healthcare facility where cardiac monitoring is readily available. This consists in compensating the possible electrolyte disturbances (mostly potassium levels), giving digitalis derivatives in intravenous route to slow down the heart rate with a chance of self-converting, or administering pharmacological therapy (amiodarone, propafenone) or electric shock (if hemodynamically unstable). After converting into sinus rhythm, proper therapy to maintain this rhythm should be instituted. I hope I was helpful. Take care.