Concerns With Taking Both Metoprolol and Propafenone
In our latest question and answer, the pharmacist discusses a reader's concerns regarding taking two seemingly similar drugs, metoprolol and propafenone.

Question
I’ve been experiencing a racing heart and was prescribed metoprolol 50 mg once daily by one doctor, and propafenone 425 mg every 12 hours by another. I’ve noticed dizziness, which seems to be a side effect of the propafenone. Based on what I’ve read online, the two medications appear to do similar things—do I really need to be taking both?

Answered by Dr. Brian Staiger, PharmD
Medical Content Reviewed By HelloPharmacist
Staff
Last updated May 13, 2025
Answer
Thanks so much for reaching out!
I want to start off by stating that it’s not totally clear what your exact diagnosis is. A “racing heart” can point to several things, such as: atrial fibrillation, SVT (supraventricular tachycardia), inappropriate sinus tachycardia, or even something like anxiety.
Each of those has different treatment goals, so knowing the root cause really matters when you’re trying to figure out if both meds are necessary. Regardless, your question is more medication-focused, so let's dive into those.
Differences Between Metoprolol and Propafenone
Metoprolol is a cardioselective beta blocker (beta-1 blocker specifically). You'd likely hear it just referred to as a 'beta-blocker'. It slows the heart rate, reduces how hard the heart pumps, and lowers blood pressure. It’s commonly used to control rate in arrhythmias like AFib or for general heart protection in people with high blood pressure or a history of heart issues.
Propafenone is a Class IC antiarrhythmic. It works by slowing electrical signals in the heart, helping to prevent irregular rhythms from forming or recurring, especially atrial fibrillation. It also has some mild beta-blocking properties, which adds to the confusion here, but its primary role is to maintain sinus rhythm, not just slow the heart.
So yes, both drugs affect heart rhythm and rate, but they do it in different ways and are often prescribed together, especially for the treatment of certain diagnoses.
You're certainly correct to be concerned with the side effect of dizziness with propafenone and metoprolol. Both can cause that, and as you mentioned, you're experiencing it. Taking both drugs increases the risk of it happening.
Dizziness could be related to how your body’s responding to the drugs in a general sense, or it could be because the drugs are dropping your heart rate or blood pressure too low.
Either way, it’s worth talking to your cardiologist to make sure this combo is right for you. It's important that you don't stop either med on your own if they were both prescribed by the same doctor, but be sure to discuss what is occurring so you can be appropriately monitored and treated.
Final Words
Overall, it's not unusual that metoprolol and propafenone would be prescribed together. They can have additive side effect, so it's important to understand what you are being treated for, and why you are taking those particular drugs. I recommend speaking to your doctor about it as they know your exact treatment details.
If you have any other drug related questions though, we're here for you!
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Dr. Brian Staiger, PharmD
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