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|Date: December 15, 2004||HC# 080641-270|
Re: Safe and Effective Use of Herbal Sedatives in Complementary Cancer Care
Block K, Gyllenhaal C, Mead M. Safety and efficacy of herbal sedatives in cancer care. Integrative Cancer Therapies. 2004;3(2):128-148.
Insomnia and other sleep disturbances are common in cancer patients. Long-term use of sleep-inducing drugs such as benzodiazepines is associated with dependence, side effects, and other risks. Non-pharmacologic strategies for improving sleep quality are needed for integrative cancer care. The purpose of this article was to explore the safety and efficacy of herbal sedatives and sleep agents for people with cancer. The article includes summaries of key herbal constituents and mechanisms of action, results of clinical trials on sleep quality, and adverse effects and safety concerns.
Valerian root (Valeriana officinalis) has been used since the 17th century for its mild sedative and tranquilizing properties. Monoterpenes and sesquiterpenes in the essential oil can inhibit the breakdown of gamma-aminobutyric acid (GABA, a neurotransmitter or chemical messenger) in the nervous system, which leads to sedation. Multiple randomized, controlled clinical trials show relief of insomnia when valerian is given for longer than two weeks, and several uncontrolled trials suggest improvement in sleep quality. Valerian may also have anti-anxiety properties. Because insomnia, fatigue, and anxiety are highly correlated in cancer patients, anxiety relief may contribute to better sleep quality. No serious side effects have been reported with normal doses of valerian and it appears to have a wide margin of safety. There is no evidence of interactions with chemotherapy drugs or other drugs commonly used by cancer patients.
Kava (Piper methysticum) has a long history of use in Pacific Island populations as a ceremonial and tranquilizing beverage. It is currently used to relieve anxiety and sleep disorders. Kava root contains kavalactones that act as sedatives and central nervous system depressants, apparently by influencing the uptake of the neurotransmitters GABA and noradrenaline (a neurotransmitter). Several randomized, controlled clinical trials show relief of anxiety and insomnia in people taking kava. Although kava has a long history of safe use in South Pacific populations, there are recent reports of liver toxicity with use of kava supplements. There is also a potential for interactions between kava and drugs that are metabolized by the cytochrome P450 enzymes. For this reason, people who are undergoing cancer treatment or taking cancer-related medications should avoid kava products.
Tea made from the flowers of chamomile (Matricaria recutita) has long been a popular bedtime beverage. Chamomile has very mild sedative effects that are attributed to apigenin, a flavonoid that binds to benzodiazepine receptors in the central nervous system. There are no controlled clinical trials demonstrating beneficial effects of chamomile on insomnia or anxiety. Rare adverse effects of chamomile include allergic reactions and contact dermatitis. Animal studies indicate chamomile may interact with anthracycline drugs, and patients undergoing chemotherapy with anthracyclines should avoid chamomile.
Aromatherapy with lavender oil (Lavandula angustifolia) is used as a sedative and animal studies suggest lavender oil has sedative and anxiety-reducing effects. However, there are no controlled clinical trials demonstrating beneficial effects of lavender on insomnia or anxiety. There are anecdotal and historical accounts of sleep-enhancing benefits of hops (Humulus lupulus) and lemon balm (Melissa officinalis). No controlled clinical trials support their use in insomnia, but uncontrolled trials suggest calming effects of these herbs. Passionflower (Passiflora incarnata) is also reported to be a mild sedative. One controlled trial indicated that passionflower had similar sedative effects as the drug oxazepam. St. John's wort (Hypericum perforatum) has clinical support for its effects in treatment of mild to moderate depression. There is some evidence that sleep improvement may accompany relief of depression. However, St. John's wort interacts with the chemotherapy drug irinotecan and has the potential to interact with other drugs.
The authors conclude that valerian and kava have the strongest clinical research to support their use in insomnia and other sleep disorders. They caution that reports of liver toxicity make kava unsuitable for use in cancer patients. The authors provide the following summary points: (1) much work remains to be done on the long-term safety and efficacy of herbal sedatives in cancer patients, the elderly, and others who take multiple drugs for chronic conditions, (2) cancer care providers should ask patients about the use of herbal products and document any such use in the patient's medical record, and (3) future research should identify the active components of herbs, investigate their stability in various formulations, and further the cause of standardization of herbal ingredients.
This article provides a thorough review of the safety and efficacy of herbs for use in insomnia and anxiety-related sleep disorders as well as extensive information on the causes and treatment of insomnia and an excellent discussion of herbal products in general. The article may be particularly valuable for practitioners or patients who are not familiar with herbal products.
—Heather S. Oliff, Ph.D.