Penn State Department of Family and Community Medicine, Penn State College of Medicine, Hershey (Dr. Malone); Torrance Memorial Physician Network, Calif (Dr. Tsai) malm0001@hotmail.com
The authors reported no potential conflict of interest relevant to this article.
Petasites hybridus, also known as butterbur, is a member of the daisy family, Asteraceae, and is a perennial plant found throughout Europe and Asia.13 It was used as a remedy for ulcers, wounds, and inflammation in ancient Greece. Its calcium channel-blocking effects may counteract vasoconstriction and play a role in preventing hyper-excitation of neurons.14 Sesquiterpenes, the pharmacologically active compounds in butterbur, have strong anti-inflammatory and vasodilatory effects through lipoxygenase and leukotriene inhibition.14
Migraine headache.Butterbur appears to be effective in migraine prophylaxis. Several studies have shown butterbur to significantly reduce the number of migraine attacks per month when compared with placebo. In a small, randomized, placebo-controlled, parallel-group study on the efficacy and tolerability of a special butterbur root extract (Petadolex) for the prevention of migraine, response rate was 45% in the butterbur group vs 15% in the placebo group. Butterbur was well tolerated.15 Similar results were found in another RCT in which Petasites (butterbur) 75 mg bid significantly reduced migraineattack frequency by 48%, compared with 26% for the placebo group.16 Petadolex was well tolerated in this study, too, and no serious adverse events occurred. Findings suggest that 75 mg bid may be a good option for migraine prevention given the agent's safety profile.
Butterbur appears to be effective in migraine prophylaxis, but there are serious concerns about liver toxicity.
Petadolex may also be a good option in pediatric migraine. A 2005 study in children and adolescents found that 77% of patients experienced a reduction in attacks by at least 50% with butterbur. Patients were treated with 50 mg to 150 mg over 4 months.17
In their guidelines for migraine prevention, the American Academy of Neurology (AAN) and American Headache Society gave butterbur a Level A recommendation and concluded that butterbur should be offered to patients with migraine to reduce the frequency and severity of migraine attacks.18 However, the AAN has since changed its position, stating that “The 2012 AAN guideline, ‘Evidence-based guideline update: NSAIDS and other complementary treatments for episodic migraine prevention in adults’ has been retired by the AAN Board of Directors on September 16, 2015, due to serious safety concerns with a preventative treatment, butterbur, recommended by this guideline. The recommendations and conclusions in all retired guidelines are considered no longer valid and no longer supported by the AAN.”19
Allergic rhinitis. Although the data is not convincing, some studies have shown that butterbur may be beneficial for the treatment of allergic rhinitis.20,21
Adverse effects
While the butterbur plant itself contains pyrrolizidine alkaloids (PA), which are hepatotoxic and carcinogenic, extracts of butterbur root that are almost completely free from these alkaloids are available. (Patients who choose to use butterbur should be advised to use only products that are certified and labeled pyrrolizidine alkaloids free.)
Petadolex, the medication used in migraine studies, was initially approved by the German health regulatory authority, but approval was later withdrawn due to concerns about liver toxicity.22 In 2012, the United Kingdom’s Medicines and Health Care Products Regulatory Agency withdrew all butterbur products from the market due to associated cases of liver toxicity.22 Petasites (butterbur) products are still available in the US market, and the risks and benefits should be discussed with all patients considering this treatment. Liver function monitoring is recommended for all patients using butterbur.22
The herb can also cause dyspepsia, headache, itchy eyes, gastrointestinal symptoms, asthma, fatigue, and drowsiness. Additionally, people who are allergic to ragweed and daisies may have allergic reactions to butterbur. Eructation (belching) occurred in 7% of patients in a pediatric study.17
The bottom line
Butterbur appears to be efficacious for migraine prophylaxis, but long-term safety is unknown and serious concerns exist for liver toxicity.