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?

Asked by Cham On May 10, 2025

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published May 11, 2025
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!

References

  • Clinical experience with propafenone for cardiac arrhythmias in the young, PubMed
  • Toprol XL Prescribing Information, PubMed
  • RYTHMOL Prescribing Information, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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