Wednesday, March 04, 2009

CAM Paper Part VII: Herbal Remedies II

Benign Prostatic Hyperplasia
Saw palmetto extract can be used to treat benign prostatic hyperplasia (BPH). It inhibits 5-α-reductase, the same enzyme inhibited by the prescription drug finasteride, thereby preventing the conversion of testosterone to dihydrotestosterone. Studies show that saw palmetto is efficacious and generally well-tolerated. Other natural products used to treat BPH include pygeum and stinging nettle. Pygeum works by a different, poorly understood mechanism. The limited published data support its efficacy, and it is well-tolerated. There is no evidence to support the use of stinging nettle for BPH.(13)

Menopause Symptoms
Black cohosh and soy are two commonly used natural products that may provide some relief to post-menopausal women suffering from symptoms like hot flashes, night sweats, vaginal dryness, mood disturbance, and poor sleep. Soy, as mentioned previously, has few side effects except that there is potentially a risk in women with a history of breast cancer due to the phytoestrogens. Black cohosh is thought to work by stimulating estrogen receptors, although it is not an estrogen analog. As with soy, there is a possible risk due to black cohosh in women with a history of breast cancer. In addition, black cohosh has been associated with liver damage in rare cases. Other natural products sometimes used to treat menopausal symptoms include dong quai and evening primrose oil. Neither of these extracts has been shown to have any efficacy.(13)

Although bioidentical hormone replacement therapy (BHRT) is actually a synthetic product, some women prefer it since the hormones are identical to the hormones present in pre-menopausal women. In contrast, prescription drugs like Premarin, which actually is a natural product, contain different estrogens that are not present in humans. BHRT is customized for each woman, which may help decrease the incidence of side effects. As with conventional hormone replacement therapy, BHRT should be used at the lowest possible dose for the shortest required amount of time. The risks of BHRT are thought to be similar to the risks due to HRT, possibly including increased chances of cardiovascular events, breast cancer, endometrial cancer, and clots.(13)

St. John’s Wort is a popular natural product used to treat depression. The extract contains several compounds that are thought to affect mood, probably by inhibiting reuptake of monoamines. This mechanism of action is similar to the mechanism of TCAs. However, there is also evidence that the active components of St. John’s wort affect other neurotransmitters like GABA and glutamate as well. There is evidence that St. John’s wort is effective in mild to moderate depression, but not in severe depression. Common side effects include GI upset, skin reactions, and sexual side effects. More worrisome is that St. John’s wort has many interactions with other drugs since it induces multiple CYP 450 enzymes. St. John’s wort may also be teratogenic and should not be used by pregnant women. Finally, since St. John’s wort prevents the reuptake of serotonin, it should not be used along with serotonergic prescription drugs such as MAOIs and SSRIs because of the possibility of serotonin syndrome.(13)

Other natural products that are used for depression include SAMe, inositol, and omega-3 fatty acids. The data for SAMe suggests that it has some efficacy in depression, but SAMe can cause a manic episode if it is taken by bipolar patients. The data on omega-3 fatty acids also are suggestive of efficacy in depression. However, the data for inositol are too preliminary for it to be recommended currently. Regardless of which agent is given, any patient with depression, especially major depression, requires psychiatric care.(13)

Insomnia and Anxiety
The sleep-inducing properties of kava kava are well known. Kava kava extract rapidly induces sleep and does not seem to cause any long-term side effects during the day following its use. Although kava kava appears to be efficacious in treating anxiety and insomnia, it has been banned in several countries due to its potential to cause serious side effects. Specifically, several case reports of patients who developed hepatitis severe enough to require a liver transplant have been published. At this time, kava kava is still available in the United States as an unregulated dietary supplement. However, it should not be used by alcoholics or other patients who have liver disease.(15)

Valerian is a safer and therefore more promising alternative to kava kava for insomnia and anxiety. It appears to induce a natural sleep pattern after being used for several weeks, and there is no evidence that it is habit-forming or has any significant side effects other than causing vivid dreams. The one potential downside of valerian is that the onset of action is several weeks, and patients may need to use a stopgap hypnotic like a benzodiazepine while waiting for the valerian to take effect. However, although valerian does not seem to effectively induce sleep acutely, it does aid with maintaining good sleep patterns over the long term. It also appears to decrease sleep latency and increase the amount of slow-wave sleep, both of which promote a greater feeling of being well-rested the following day. These qualities may make valerian useful as a treatment for chronic insomnia, especially in the elderly.(15)

Another promising herbal treatment for insomnia and anxiety is aromatherapy with essential oils like lavender and chamomile. Lavender is commonly used as the oil rather than ingested, while chamomile is usually ingested as a tea. In both cases, it appears to be inhalation of the essential oil that produces the hypnotic effect.(15)

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