Researchers warn against supplement consumption alongside prescribed heart drugs

By Nathan Gray

- Last updated on GMT

Related tags Vitamins Dietary supplement

Patients with heart problems may be causing mroe complications by taking vitamin supplements that interfere with medications, warn the researchers.
Patients with heart problems may be causing mroe complications by taking vitamin supplements that interfere with medications, warn the researchers.
Heart patients who take vitamins and supplements are less likely to take medications as prescribed, and may also be increasing the risk of further complications by interfering with the effectiveness of the drugs they need for recovery, warn researchers.

The research – presented at the American Heart Association Scientific Sessions​ – reports that atrial fibrillation patients who take vitamin supplements are less likely to follow the directions on their medication, and are more likely to miss doses.

The research team, from the Intermountain Medical Center, USA, also said that doctors need to further educate patients about mixing vitamins and supplements with the highly prescribed blood thinner warfarin because vitamins and nutritional supplements can reduce the effectiveness of the drug, therefore increasing the risk of stroke.

"Vitamins are highly active substances,"​ said Dr. Jeffrey L. Anderson, one of the researchers responsible for the findings.

"When you take a vitamin pill, you often are getting a much higher dose than you would by just eating a balanced diet. People don't realize that vitamins can be just as active as drugs, and, as we've seen here, mixing the two together can, in some cases, have adverse consequences for your health."

Anderson added that he is ‘troubled’ by the results, as they indicate that physicians “need to do a better job of educating our patients about vitamins and other supplements and how theyinteract with the medications we prescribe."

Study details

To learn how patients comply with their warfarin prescriptions, the research team administered a 52-item questionnaire to 100 randomly recruited patients previously diagnosed with atrial fibrillation.

Each patient had a face-to-face interview with a dietician who asked them about their knowledge of warfarin and their compliance with the prescribed regimen. They were also asked about their use of vitamins and dietary supplements.

Of the 62% who reported using a vitamin supplement, 24% admitted skipping doses of warfarin, said the researchers, who added that compared to those not taking vitamins, such patients were also found to be 2% more likely to double their dose of medication.

Anderson and his colleagues also reported that vitamin users were less aware of the potential for vitamin-warfarin interactions (37% to 30%), however the researchers said that of the most concern, they found patients who took vitamins had more episodes of unexplained bleeding, and required more non-surgical transfusions.

Vitamin risks?

Anderson said that while the use of vitamins and other dietary supplements continues to rise – especially in the USA – very few people have a good understanding of the consequences of taking them – adding that there is a common misperception that ‘if some is good, more must be better’.

"More and more studies are starting to show that excessive doses of some vitamins can increase the risk for serious diseases, including cancer,"​ said Anderson.

"As health care providers, we need to encourage caution when it comes to taking vitamins, as with any other medications,"​ he stressed.

The researcher said that doctors need to ask patients about their vitamin use, and that patients need to be candid with their physicians about any vitamins and other supplements they might be taking.

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Posted by Dr Matti Tolonen,

This news is nothing but unspecified nonsense directed against dietary supplements. Many drugs can change the International Normalized Ratio (INR), i.e., the time it takes for blood to clot. These drugs include aspirin, ibuprofen, antibiotics, and birth control pills/progesterone-estrogen combination pills. Should they all be skipped, if you take Warfarin?

Furthermore, foods high in vitamin K, a natural blood-clotting factor, can alter an INR. Broccoli, lettuce, spinach and liver are all high in vitamin K. Doctors usually encourage patients to include these nutritious foods in a healthy diet. Should they now drastically change their eating habits to unhealthy ones due to Warfarin?

Many cardiologists now recommend dietary supplements, e.g. ubiquinone (CoQ10) as a dietary supplement for heart patients.

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Interfering with Medication Effectiveness?

Posted by Rob,

This summary of the study didn't mention what specific interactions were found between vitamins and heart medications. I suspect the study didn't find any and that everything in it was simply correlative rather than causative. For example, it mentioned that people using vitamins were more likely to skip a dose, double a dose, and have episodes of unexplained bleeding. Those were the only specifics mentioned. None of these are necessarily caused by vitamins themselves but seemed rather to be a launching point for the study authors to further try and denigrate vitamins with vague comments about them causing cancer as well...Of course being cautious about not taking excessive amounts of vitamins is wise but this study doesn't seem to offer anything very meaningful or substantial beyond that.

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Concern or prejudice

Posted by Bill Pine,

Healthcare providers should be concerned about interactions; however more importantly those of prescription drugs. Being in the elderly class of the population I have spoken with many who were over medicated with prescription drugs that should be a part of the medical records. Where is the call for noting the interaction between prescription drugs. This is much more a threat than supplements and vitamins.

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