Karin Kraft, PhD
Karin Kraft, PhD, professor of medicine, University Hospital at Rostock, Germany. Her study was published in Evidence-Based Complementary and Alternative Medicine.
Imagine facing a cancer diagnosis along with its exhausting and debilitating treatment…add the responsibilities of your normal life of work and family…and then not being able to get a good night’s sleep. Insomnia and restless sleep are very common in cancer patients, affecting three-quarters of them. These sleep problems are not only related to the stress of having cancer but the side effects of cancer treatment, such as pain, night sweats (hot flashes) and stomach/intestinal and respiratory problems, according to the National Cancer Institute. We also know that cancer drugs wreak havoc on the immune system, and loss of sleep compounds this attack by putting a person at even higher risk for infection while he or she is already battling a life-threatening illness.
The herb valerian is known to be great for helping a person relax and get to sleep, but conventional medical doctors have been discouraging cancer patients from using it. They claim it prevents the body from fully processing and absorbing chemotherapeutic drugs. But is this true?
Valerian relieves insomnia without the side effects of prescription sleeping pills, such as daytime grogginess, confusion, dizziness, tremor and stomach problems. But patients and doctors who read about the safety of valerian are being warned that it can interfere with anticancer chemotherapy drugs. This scares away many cancer patients who are looking for a safe alternative to sleeping pills and tranquilizers to help them relax and sleep. Are the warnings legit?
Not quite, according to a new study by German researchers published in Evidence-Based Complementary and Alternative Medicine.
The researchers took a close look at the scientific reports used as the basis for the dire warnings of valerian-drug interactions—none of which actually looked at valerian and chemotherapeutic drugs. Some were reports of lab experiments that used sophisticated techniques to measure the impact of valerian on enzymes that the body uses to metabolize drugs. The theory was that valerian increased the amount of those enzymes, which, in turn, would reduce the therapeutic action of an anticancer drug.
A few of these reports pointed to a potential that valerian could inhibit absorption of any drug metabolized by the liver, but the findings are unreliable, according to the German researchers. That’s because the quality of valerian used was not identified in the reports, and only high doses outside of the normal range were tested. What’s more…what happens in a “test tube” doesn’t always happen in the human body. This phenomenon has been shown in other studies that look at how herbal extracts affect the metabolism of pharmaceutical drugs.
In addition to studies done in test tubes in laboratories, the researchers also looked at studies using rats and mice. In these studies, valerian and the drugs it was compared with were given to lab rats and mice at doses equivalent to those that would normally be used in humans. One study that looked at the combined effects of valerian and the anti-anxiety medication alprazolam (Xanax) and another that looked at valerian combined with the antipsychotic haloperidol (Haldol) found no metabolic interactions. This means that valerian did not affect how these pharmaceutical drugs were processed by the liver or absorbed by the body.
As for interactions in humans, two reports of people using valerian in combination with pharmaceutical medications were analyzed. One report involved a man who had been using the anti-anxiety drug lorazepam (Ativan) for months before adding a combination herbal remedy that included, among other botanical products, valerian. After a few days on his new regimen, the man experienced shakiness and drowsiness, which may or may not have been caused by the valerian. In the other report, a woman hospitalized for severe delirium had reportedly been using valerian, St. John’s wort and the antidiarrheal medication loperamide (sold as Imodium AD) for months before landing in the hospital. Her doctors attributed the woman’s delirium to the herbs even though her lab tests showed that she also had been taking potent opioid painkillers, which could have caused the delirium all by themselves.
Finally, a study in 48 healthy volunteers showed that valerian combined with the blood pressure and angina drug propranolol (Inderal) did not lead to any drug interactions at all.
The German researchers concluded that these findings seriously call into question the assumption that valerian interferes with anticancer drugs.
I am all for using any drug, including botanical preparations, very carefully, and I wouldn’t ordinarily suggest that we ignore warnings of potential drug interactions. Also, know that one of the study’s authors is affiliated with Steigerwald Arzeneimittlewerk, a German pharmaceutical company specializing in herbal medicines that was recently bought by Bayer. Still, warnings should be based on evidence, and it seems that the evidence just isn’t there to back up claims that valerian will render anticancer drugs less effective.
In fact, the opposite may be true—if valerian can safely help cancer patients get the rest they need, these patients may have more energy to focus on healing and recovery while avoiding the risks associated with prescription sleep aids.