Is Black Seed Oil Safe With Metoprolol And Flecainide?

In our latest question and answer, our pharmacist discusses whether or not there are interactions between black seed oil, metoprolol and flecainide.


I am taking flecainide and metoprolol and wanted to know if it’s safe to take black seed oil.

Asked by Bernie On Jan 30, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Feb 01, 2023
Last updated Sep 29, 2023

Key points

  • Black seed oil supplements may cause a reduction in blood pressure, and therefore, could have an additive effect with blood pressure-lowering medications
  • Be sure to let your doctor know about all the medication, including supplements, you are taking.


Black seed oil supplements do have some interactions to be aware of, so I'm glad you reached out to us!

When answering questions like this, I always like to put forth the caveat that drug-herb interactions can be difficult to predict.

Drug-herb interactions not only have limited data behind them but can often depend on many factors, such as the dose and preparation of the herbal in question, as well as individual factors such as genetics and overall medical condition.

Nevertheless, let's get into your question about metoprolol and flecainide.

Black Seed Oil May Lower Blood Pressure

The primary concern between black seed oil supplements and blood pressure medication, like metoprolol, is the additive blood pressure-lowering effects.

Metoprolol is a beta-blocker that, among other things, lowers blood pressure. Black seed oil has been reported to have a mild blood pressure-lowering effect as well. One study reported:

Our meta-analysis suggests that short-term treatment with N. sativa powder can significantly reduce SBP [systolic blood pressure] and DBP [diastolic blood pressure] levels. More evidence is needed, however, to strengthen the available evidence and to further explore the long-term BP-lowering effect of N. sativa.
J Hypertens . 2016 Nov;34(11):2127-35

Please note that N.sativa stands for Nigella sativa, the scientific name for black seed.

So, theoretically, combining metoprolol and black seed oil could drop blood pressure too low. This could increase the risk of side effects, such as dizziness, sedation, and lightheadedness.

On the other hand, you could think of this interaction as a positive thing, helping to get blood pressure more under control if it is currently too high.

The important thing is that you know both can lower blood pressure and you monitor it appropriately. You should also let your doctor know of all the drugs and supplements you are taking so you can be monitored as well.

Based on the mechanism of this interaction, our 'drug-herbal interaction checker' will return a result with any blood pressure medication, such as:

What About Flecainide?

I could not find any information supporting a potential interaction between black seed oil and flecainide, a medication used to treat arrhythmias.

However, in line with the caveat I wrote about above, there is limited research on the potential interactions between flecainide and black seed. There is no clear evidence of any significant interactions but, as with any supplement or medication, it is always best to consult with your doctor before starting or stopping any new regimen so you can be assessed and monitored.

Final Words

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  • Antihypertensive effect of Nigella sativa seed extract in patients with mild hypertension, PubMed
  • A systematic review and meta-analysis of randomized controlled trials investigating the effects of supplementation with Nigella sativa (black seed) on blood pressure, PubMed
  • Metoprolol Tartrate Monograph, PubChem
  • Flecainide Monograph, PubChem

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! You can also connect with Dr. Brian Staiger on LinkedIn.

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