New Review Warns of Herb, Supplement and Drug Interactions

A new review by the American Academy of Family Physicians, which used the Natural Standard database as a source, investigated the most common herbal and dietary supplement-drug interactions associated with chronic illnesses and emphasized the need for greater awareness in this area of patient care.

Researchers from Harvard Medical School, Beth Israel Deaconess Medical Center and Tufts University explained that herbs, vitamins and other dietary supplements may increase or counteract the actions of prescription and nonprescription drugs.

The review found that approximately one in four persons taking prescription medication is also taking a dietary supplement. The review used The National Center for Complimentary and Alternative Medicine's definition of a dietary supplement and stated that a dietary supplement can be "a vitamin, a mineral, an herb or other botanical, an amino acid or other such substances or their constituents."

The review used several sources, including the Medline, Embase and Cinahl databases and an authoritative drug interaction reference. The review found that asthma, insomnia, depression, chronic gastrointestinal disorders, pain, memory problems and menopausal symptoms are the medical conditions for which supplements are most commonly used.

The review observed that patients at high risk for interactions, such as those with seizure disorders, irregular heart beat or congestive heart failure, often report dietary supplement use. These patients also tend to take more prescription medications, especially medications with a narrow therapeutic index.

The review analyzed the current regulation (or lack there of) of dietary supplements, which are not subjected to the same rigorous safety and efficacy trials and premarketing approval process required of prescription drugs. In June 2007, the U.S. Food and Drug Administration (FDA) released "good manufacturing practices" for the dietary supplement industry requiring dietary supplement ingredients to match their labels.

The researchers explained that as there is no process for systematic evaluation of dietary supplement products for possible interactions with prescription medications, the knowledge of interactions is incomplete and based on animal studies, case reports, case series, historical contraindications, extrapolation from basic pharmacology data or the clinical trial when available.

The review analyzed the interaction risks in specific patient populations including: patients taking blood thinners (anticoagulants), heart (cardiovascular) medications, psychiatric medications, laxatives, diabetes medications and medications for HIV (human immunodeficiency virus) infection.

The review authors concluded that physicians should advise patients about the safety and effectiveness of the products they are using or are considering using. Surveys suggest that two out of three patients taking prescription medications and supplements do not tell their physician about their dietary supplement use. The researchers recommended that all patients should be asked about their use of dietary supplements and these supplements should be treated as other drugs and recorded in the patient record.

Comments

[QH]

It isn’t unusual for patients to not tell their healthcare providers what herbs and supplements they may be taking, and sometimes, practitioners don’t ask about these alternative medicines. If both patients and practitioners make it more of a habit to communicate this to each other, perhaps drug interactions may be caught or identified before harm is done.

[Stella]

I can't stress enough how important it is for patients to understand that "natural" does not mean safe. Just working at the pharmacy this morning, I must have counseled three people already about this. Everyone I speak with thinks that just because it is "natural" or "from plants" or "from the Amazon" that it will not interact with any medication or cause any side effects. It troubles me so much. I wish there was a way to really get this message out.

[Jen]

I agree that this is an extremely important issue. It is very hard for healthcare practitioners to give accurate advice if that practitioner isn’t aware of all supplements being taken. Even taking a multivitamin can interact with medications. For example, there are varying amounts of vitamin K in multivitamins. If a patient taking warfarin (Coumadin®) is switching the brand of multivitamin he/she takes, it could decrease the efficacy of the warfarin, leading to more changes in drug regimens. I’m with Stella - I wish there was a way to let all consumers know that taking a supplement could be detrimental.

[Melinda]

Doctors can't expect their patients to know that they need to disclose any herbs or supplements they are taking. As the posters above have pointed out, many patients view herbs/supps as "natural" and therefore, safe. So, it's really the doctor's responsibility to ask his patients if they are taking anything.

[Mary]

St. John’s Wort is known to interact with many prescriptions medications. Some known interactions include anticonvulsants, immunosuppressants, oral contraceptives, HIV medications (protease inhibitors and non-nucleoside reverse transcriptase inhibitors), SSRIs and warfarin. However, there have been very few reports of these interactions.

[Jay]

I think that any interaction or adverse event caused from an herbal supplement or over-the-counter medication should be reported. The Dietary Supplement and Nonprescription Drug Consumer Protection Act, which went into effect on December 22, 2007, was designed to improve the adverse event reporting of dietary supplements and over-the-counter medications.

[Julie]

I agree with Melinda. We pay doctors/pharmacists plenty of money under the belief and trust that THEY are the ones with the medical knowledge and expertise. It is therefore their responsibility, when they take our money, to exercise their medical knowledge and not depend on the medical know-how of the patient. I'm not in anyway demeaning the intelligence of the patient, but there is a reason why doctors and pharmDs have to go through several years of school vs. the common patient. And for that reason, there is absolutely NO EXCUSE for a doctor or pharmacist to miss any interaction or fail to alert a patient of a potential interaction. I was recently on the antibiotic Cipro and neither my doctor nor pharmacist cared to tell me to avoid caffeine AND all vitamins/minerals when taking it. Luckily, I did my own research online. I'm tired of doctors who are happy to take our money but slow to pick up on potential hazards/interactions.

[Heather]

I agree with the comments that it is the doctor’s and pharmacist’s job to report any potential interactions and ask if a patient is taking any herbs or supplements. But, during medical/pharmacy school there is so little emphasis on this subject. I think that there needs to be more education on this topic because there is a potential for serious interactions.

[Casey]

A lot of interactions with herbs and supplements are based on animal studies, case reports and basic pharmacologic data. This makes it difficult to assess which interactions are truly important and which interactions may be minor. This means that doctors may have to do a little research in order to find most comprehensive data for their patients taking herbal medications.

[Trish]

Now that I think about it, my doctor has never asked me if I take any herbs or supplements. I don't currently take anything, and I know about the importance of disclosing that information if I did take anything. However, it makes me wonder how many of his other patients are taking supplements without his knowing.

[GM]

After reading the comments that have been left so far, there seems to be a recurring trend in thinking that doctors have an intimate knowledge of herbal medications. Doctors are not the drug experts, the pharmacists are. All of the years of schooling that they go through are focused mainly on medications. While alternative medicine is not a focal point for many pharmacists, they do have some experience with them. Many pharmacies have access to references that will provide accurate information. Patients should not rely on Internet searches, as they are often directed to misleading Web sites with misinformation. Don’t be afraid to ask your pharmacist about any over-the counter medication, they’re easily accessible and a FREE resource.

[Robert]

Good point, GM. Many doctors don't really know a whole lot about herbs and supplements. This is not really their fault though. It's not covered extensively during medical school, and there is really just limited research on the use of many herbs. However, it's still really important to talk to your doctor about anything you are taking. If he/she is unsure about potential interactions or contraindications he can refer you to someone else or encourage you to talk with your local pharmacist.

[Sandro]

I agree that doctors really need to ask their patients about herbs/supplements they are taking. However, my doctor has neglected to inform me of some very important drug interactions in the past. He prescribed me amoxicillin but did not tell me that it decreased the effectiveness of the birth control pills I was taking. I didn't find this out until later, when I had to take a home-pregnancy test (which, thankfully, was negative).

So, my main point is that patients really need to be advocates for themselves. Don't be afraid to ask your doctors lots of questions, especially about the safety of herbs and supplements you may be taking.

[Online Herbal Pharmacy]

Great. I like this story. Thanks for sharing.

[Compounding Pharmacist]

Compound pharmacy has gained much popularity in the field of medicine. The medications are equally effective and safe for sick patients who cannot take the actual medications due to their personal allergies.