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Letters to the Editor
June 2005

Addressing the Long-term Safety Aspects of Butterbur Therapy: A Call for Immediate Action

Arch Otolaryngol Head Neck Surg. 2005;131(6):539-540. doi:10.1001/archotol.131.6.539-c

Schapowal1 is to be commended for reporting the results of a carefully conducted 2-week study on the dose-response of butterbur therapy in patients with intermittent allergic rhinitis. The author’s follow-up trial of a previous non–placebo-controlled study2 sheds further light into the potential therapeutic role of butterbur in the treatment of allergic airway disease. Recent trials of butterbur in which objective measures were used have consistently shown its beneficial effects. Treatment with butterbur has been found to attenuate the response to nasal provocation testing with adenosine monophosphate compared with placebo in patients with intermittent allergic rhinitis.3 Also, when compared with fexofenadine hydrochloride, a modern histamine H1-receptor antagonist, butterbur has been demonstrated to confer protection against nasal adenosine monophosphate challenge while improving nasal symptoms in patients with persistent allergic rhinitis.4 Importantly, the anti-inflammatory effects of butterbur are not confined only to the upper airway but also extend into the lower airway, where, compared with placebo, butterbur has been shown to improve airway hyperreactivity after bronchial adenosine monophosphate challenge in patients with asthma who were receiving inhaled corticosteroids.5

Sadly, however, despite the optimism regarding the use of butterbur in the literature, one pertinent question remains unanswered: what about possible adverse effects from long-term butterbur therapy? Although the current study did not demonstrate any adverse effects, it should be emphasized that butterbur therapy was evaluated for only a 2-week period. In a previous study in which butterbur was taken by patients with intermittent allergic rhinitis, also only for 2 weeks, liver function appeared to be unaffected.3 However, unpurified butterbur contains toxic pyrrolizidine alkaloids, which have been linked to hepatotoxicity and carcinogenicity in humans, and testosterone production has been shown to be inhibited by butterbur in animals, so no one can really be sure whether the use of butterbur, albeit in its purified form, may have any potential deleterious effects in the long-term. Therefore, as with any licensed therapy, herbal or otherwise, long-term studies should be carried out to investigate the safety aspects of butterbur therapy.

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Article Information

Correspondence: Dr Lee, Department of Respiratory Medicine, Ipswich Hospital, Heath Road, Ipswich IP4 5PD, Suffolk, England (dkclee@doctors.org.uk).

Schapowal  A Butterbur Ze339 for the treatment of intermittent allergic rhinitis: dose-dependent efficacy in a prospective, randomized, double-blind, placebo-controlled study.  Arch Otolaryngol Head Neck Surg 2004;1301381- 1386PubMedGoogle ScholarCrossref
Schapowal  A Randomised controlled trial of butterbur and cetirizine for treating seasonal allergic rhinitis.  BMJ 2002;324144- 146PubMedGoogle ScholarCrossref
Lee  DKCarstairs  IJHaggart  KJackson  CMCurrie  GPLipworth  BJ Butterbur, a herbal remedy, attenuates adenosine monophosphate induced nasal responsiveness in seasonal allergic rhinitis.  Clin Exp Allergy 2003;33882- 886PubMedGoogle ScholarCrossref
Lee  DKGray  RDRobb  FMFujihara  SLipworth  BJ A placebo-controlled evaluation of butterbur and fexofenadine on objective and subjective outcomes in perennial allergic rhinitis.  Clin Exp Allergy 2004;34646- 649PubMedGoogle ScholarCrossref
Lee  DKHaggart  KRobb  FMLipworth  BJ Butterbur, a herbal remedy, confers complementary anti-inflammatory activity in asthmatic patients receiving inhaled corticosteroids.  Clin Exp Allergy 2004;34110- 114PubMedGoogle ScholarCrossref