Allergic rhinitis is characterized by inflammatory nasal congestion and restriction to airflow in the nose, as a response to substances like pollen and dust mites. Antihistaminic drugs like cetirizine and fexofenadine are used to treat this condition. A previous study compared the efficacy of an herbal drug derived from the butterbur plant with cetirizine. This study compared the herbal drug and fexofenadine along with a placebo containing no active ingredients in a randomized, double-blind, placebo-controlled environment. It was found that the herbal drug was as effective as fexofenadine in treating the condition. The study points to the possible role of butterbur in treating allergic rhinitis.
Allergic rhinitis is a disorder of allergic response of the lining of nasal passage to inhaled substances. The allergic response is characterized by inflammation of the nasal lining by release of substances called histamine. Drugs like fexofenadine block the action of histamine. A product from the plant butterbur is known to inhibit the synthesis of histamine and other inflammatory markers like leukotrienes. In a previous study, butterbur was compared with an antihistamine agent cetirizine. However, that study did not involve documentation of placebo response. The present study evaluated the effects of butterbur and the drug fexofenadine, in comparison to placebo. It measured the objective outcome of nasal responsiveness to allergic challenge and the subjective outcome of nasal symptoms.
* In this study, 16 patients with allergic rhinitis participated. Skin testing for allergic response to house dust mites, cats, dogs, grass, trees and weed pollen was performed in all participants.
* The participants received a single dose of adenosine monophosphate (AMP) administered via a pump spray device in the nostrils, to induce local allergic response.
* They received a one-week therapy of butterbur, the antihistaminic drug fexofenadine or placebo containing no active ingredient. All the tablets were identical in external appearance. The patients switched in between the three types of tablets progressively.
* Obstruction to airflow in nasal passages was documented by recording peak nasal inspiratory flow at baseline and after the experiments.
* The patients recorded their nasal symptoms for five days, based on a four-point scoring scale. On this scale, zero indicated no symptoms and three indicated severe symptoms.
* Before allergic challenge, the baseline airflow measured by peak inspiratory airflow measurement was 138 L/min for butterbur group. The corresponding values were 140 L/min for fexofenadine group and 138 L/min for placebo group.
* The fall in peak inspiratory airflow immediately after nasal challenge was 18 percent for butterbur group. The corresponding values were 24 percent for fexofenadine group and 29 percent for placebo group.
* The fall in peak inspiratory airflow one hour after the nasal challenge was 9 percent for butterbur group. The corresponding values were 18 percent for fexofenadine group and 24 percent for the placebo group.
* The mean of nasal symptom score (maximum value 12) was 2.8 for the placebo group, while it was 1.8 for both butterbur and fexofenadine groups.
The study lasted for six weeks, including three weeks of washout period during which no therapy was provided. It included just 16 participants. The short duration and small number of participants are the shortcomings of this study. The study tested the airflow and symptomatic ratings provided by the participants. Actual nasal biopsy or examination of tissue obtained by washing nasal passages could be better indicators of suppression of allergic response.
Allergic rhinitis is often treated by intranasal corticosteroids or antihistaminic drugs. This study conducted on patients suffering from allergic rhinitis, showed that an herbal preparation made from plant butterbur is as effective or more as the antihistaminic drug fexofenadine that is being currently prescribed. The study was better designed than a previous one, as it included testing response to placebo. If findings of the earlier study comparing butterbur and drug cetirizine are pulled together with findings of this study, it can be said that this herbal preparation worked similar to current drugs prescribed for control of allergic rhinitis. However, more research is needed to determine whether the herbal drug is superior to the drugs being currently prescribed.
For More Information:
A Placebo-Controlled Evaluation of Butterbur and Fexofenadine on Objective and Subjective Outcomes in Perennial Allergic Rhinitis
Clinical and Experimental Allergy, 2004
By D. Lee; R. Gray; Asthma & Allergy Research Group, Ninewells Hospital & Medical School, University of Dundee, Dundee, Scotland
*FYI Living Lab Reports Are Summaries of the Original Research.