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WASHINGTON, Aug 22, 2005 (United Press International via COMTEX) -- An herbal extract may treat seasonal allergies just as effectively as antihistamine drugs without the risk of drowsiness, a new study by Swiss and German researchers has found.
The study, published in the journal Phytotherapy Research, tested extract of butterbur, a plant found in Europe, Asia and parts of North America. Butterbur's roots have been used medicinally for centuries, but the plant's leaves have only recently come into use as an herbal medicine. Both the leaves and the roots contain petasines, chemicals that inhibit the body's ability to produce leukotrienes, components of an allergic reaction.
"You often know from the history of medicine that an herbal extract most probably has quite good efficacy in a certain disease or in certain symptoms, which is a good starting point for in vitro and animal research," lead researcher Andreas Schapowal told UPI. "In synthetic chemicals, a lot more manpower and computer work has to be done for finally maybe luckily finding an active drug with reasonable efficacy and low toxicity."
Schapowal said the butterbur extract used in the study, Ze 339 from Zeller AG of Romanshorn, Switzerland, is the only herbal drug licensed for intermittent allergic rhinitis. He said it has been on the Swiss market since June 2003 and is covered under Swiss health insurance.
Products containing butterbur extract are commercially available in the U.S. under the names Migravent and Petadolex but have not been evaluated by the Food and Drug Administration. According to an estimate cited in the study, approximately 20 percent of the population in industrialized nations suffers from allergic rhinitis, commonly known as hay fever. Symptoms include sneezing, runny nose, nasal congestion and itching of the mucous membranes. In some patients the condition also leads to headaches, fatigue and reduced work and social functioning.
The main treatments at this point are antihistamines. These are effective in reducing runny nose and sneezing, but drowsiness is a common side effect, even to some degree for newer non-drowsy antihistamines, according to the study.
Patients in the study received either pills made from butterbur extract, fexofenadine or a placebo. Fexofenadine, a non-drowsy antihistamine, is sold as Allegra in the U.S. and as Telfast 180 in Europe.
The butterbur and fexofenadine groups achieved similar changes in total symptoms scores. These changes were statistically significant, while the placebo group did not experience statistically significant change.
Side effects occurred at similar rates in all treatment groups. Three-quarters of side effects in the fexofenadine group were related to sedation, compared to just over one-third in the groups receiving placebos or butterbur.
"Because butterbur does not cause the sort of drowsiness that is so often associated with other antihistamines, it could be particularly useful for patients who cannot tolerate other therapies," Schapowal said.
Schapowal was also the lead author of a 2002 study in the British Journal of Medicine finding that butterbur had similar curative effects and reduced drowsiness relative to cetirizine, another non-drowsy antihistamine. Cetirizine is sold in the U.S. under the name Zyrtec.
A 2004 study by U.S. and German researchers in the journal Neurology found that butterbur root is also an effective treatment for migraines.
The butterbur plant cannot be consumed in its raw form because it contains pyrrolizidine alkaloids, which can cause potentially fatal liver damage. Schapowal said Ze 339 is made from only the leaves of a special plant in controlled cultivation and uses carbon dioxide extraction to bring the level of pyrrolizidine alkaloids below 35 parts per billion, the level of detection. No abnormal liver functions were detected in the group of patients receiving the butterbur extract in the study.
Copyright 2005 by United Press International.