FEVERFEW

Occurrence

Feverfew is a perennial found throughout the world.

The Uses of FEVERFEW

Feverfew is used traditionally to treat menstrual irregularities, threatened spontaneous abortion, arthritis, and fever.

Indications

Feverfew (Tanacetum parthenium) is a common European composite herb with daisylike white flowers now widely naturalized in the United States.While its name (a corrupted version of the Latin febrifugia) indicates a long history in herb lore, feverfew’s current popularity is due to its use in the prevention and treatment of migraines. Feverfew has also been used for rheumatoid arthritis and numerous other conditions with far less substantiation. The leaves contain sesquiterpene lactones, including parthenolide, which is thought to be the most active and important ingredient. Feverfew preparations are frequently standardized for parthenolide content, which can vary substantially depending on time of harvest (levels drop after seeds form) and other factors. Most studies have used feverfew standardized to 0.6 to 0.7% parthenolide; the value of leaves containing less than 0.2% parthenolide is questionable.

General Description

Feverfew, Tanacetum parthenium (L.) Schultz Bip, is an herb that was used in antiquity to reduce fever and pain. The literature is replete with anecdotal evidence of the usefulness of the herb, and recent clinical studies have added more support. Feverfew is a member of the aster/daisy family. The plant tissues have a pungent smell and very bitter taste. The medicinal principle of feverfew is concentrated in hairy trichomes on the chrysanthemum-like leaves.The plant displays clusters of daisylike flowers with yellow centers and radiating white florets. Recent uses of feverfew are for migraine and arthritis, although the indication for arthritis is disputable. The anecdotal evidence that an herb could successfully treat a condition such as migraine headache, naturally begged for some scientific proof. Two prospective clinical studies using dried whole feverfew leaf have been performed to assess the value of the herb in migraine. The two leaf studies on migraine provided good supportive evidence for activity of the herb against migraine.

Mechanism of action

Parthenolide inhibits serotonin release, an action that is thought to be a likely source of its effectiveness in migraine. Extracts have also been shown to reduce the production of prostaglandins (another possible mechanism) and leukotrienes. Interestingly, melatonin has been identified in feverfew, a possibly significant observation, since chronic migraines have been associated with low melatonin levels.

Clinical Use

At least three studies have demonstrated that feverfew (dried leaf, not extract) can reduce the frequency and severity of migraine headaches, although one study failed to find any significant difference from placebo. Prophylaxis appears to be more effective than acute treatment. There is also a consensus that feverfew is probably less effective than conventional migraine prophylaxis, although it may have a role as a second-line option. Although feverfew has also been used for rheumatism, it has never been verified to be effective in clinical trials.

Side Effects

Although feverfew appears generally safe in nonpregnant adults, the use of fresh leaves has caused mouth irritation and even ulceration. This is far less likely to occur when the herb is encapsulated. Allergic reactions (contact dermatitis) have occurred with topical use in sensitized individuals, and ingestion may also produce allergic reactions in people with preexisting allergies to members of the Compositae family. Feverfew has caused contractions in term pregnancy and has been implicated in cattle abortions and so should be avoided in pregnancy and lactation. A feverfew withdrawal syndrome consisting of joint pain and muscle stiffness may occur following abrupt discontinuation. Theoretically, because of its antiprostaglandin effects, feverfew should not be coadministered with anticoagulants or antiplatelet drugs.