Science is working to prove modern uses of herbs. One of these these herbs is butterbur, Petasites hybridus. Butterbur extracts contain numerous constituents, many of which have unknown effects.There are expected responses to both prescription drugs and herbal remedies. Undesired responses to drugs and herbal remedies are side effects.
Pyrrolizidine alkaloids commonly occur in plants as bitter constituents to protect the plant from being eaten. Human gut bacteria reduces the toxicity of pyrrolizidine alkaloids, only to have them metabolized by the liver to toxic carcinogenic derivatives. According to scientists, large amounts of pyrrolizidine alkaloids can cause liver toxicity. Two of these pyrrolizidine alkaloids, senecionive and ingerrmine, are contained in small amounts in butterbur root and lesser amounts in butterbur leaf. This is of concern because the root is used medicinally for migraine headache prevention. Butterbur supplements identified as "pyrrolizidine free" are the best ones to use. If buttterbur is taken more than six consecutive weeks per year, a pyrrolizidine-free product must be used to avoid potential toxicity. A product free from pyrollizidine alkaloids is not necessarily free from side effects. Liver damage can result from buildup of these activated pyrollizidine alkaloids in the liver, in the form of benign and malignant tumors.
Medicinal Forms of Butterbur
Butterbur may be taken medicinally as an alcohol based tincture, an herbal tea, or a pill. Teas and tinctures are not recommended because the bitter taste is unpalatable. The best way to take butterbur as a tablet or capsule as both readily dissolve in the stomach without the unpalatable bitter taste..
According to the American Botanical Council, the medicinal effects of butterbur result from the bitter tasting constituents petasin and iso-petasin found in the root. Current studies on butterbur focus on the benefits of the herb, as most of the herb available in the market is pyrrolizidine free. The most common side effect from ingesting butterbur pills are due to its bitter constituents. These side effects are burping, nausea, and stomach pain.
Scientists have reported rare,temporary allergic skin reactions from long term butterbur ingestion. Even more unusual--reported in only three cases to date, is the incidence of raised liver markers in individuals using butterbur for prolonged periods. In each case, the liver markers returned to normal after discontinuing butterbur use. Liver function tests are required for long-term butterbur use.
Increased risk of side effects occurs in individuals who abuse alcohol and who have compromised liver function.
Use of butterbur in pregnant and nursing women has not been studied and is contraindicated. The same applies for children under 12 years and women who may become pregnant.