Platelet aggregation inhibition feverfew

A contact dermatitis occurs infrequently. Because feverfew also inhibits human blood platelet aggregation, interactions are possible with antithrombotic medications such as aspirin or warfarin (Groenewegen and Heptinstall 1990). Abrupt discontinuation of feverfew by people taking it chronically for treatment of migraine can produce rebound withdrawal symptoms. These consist of migraines, anxiety, poor sleep patterns, and stiffness of the muscles and joints. 

Feverfew is widely consumed in England as a remedy for arthritis and migraine. Feverfew contains parthenolide, which is a member of sesquiterpene. Parthenolide inhibits the activity of prostaglandin synthetase. It also inhibits platelet aggregation and alter serotonin release (Figure 25.2). 

Feverfew is most often used as a prophylactic remedy for migraine headache. This action has been related to the serotonin hypothesis for migraine causation (see also Chapter 16 Histamine, Serotonin, the Ergot Alkaloids). In vitro, feverfew and parthenolide inhibit platelet aggregation and serotonin release from platelets. 

Patients taking anticoagulant and antiplatelet drugs should use feverfew cautiously, because the herb may inhibit platelet aggregation. 

Feverfew inhibits platelet aggregation (45), and its concomitant use with anticoagulants such as warfarin is therefore not advised. 

Ginger, which inhibits thromboxane synthase and decreases the rate of platelet aggregation, may increase bleeding time. Feverfew, which also inhibits platelet activity, should also be avoided. 

While some in vitro studies have indicated that feverfew can inhibit platelet aggregation (Loesche et al. 1988 Makheja and Bailey 1982), no effects on aggregation were observed in the one human study of feverfew and aggregation (Biggs et al. 1982), and no cases of bleeding in association with feverfew have been reported (Stargrove et al. 2008). 

Extracts of feverfew have inhibited human platelet aggregation in vitro (Groenewegen and Heptinstall 1990 Heptinstall et al. 1987, 1988 Loesche et al. 1988 Makheja and Bailey 1982). 

Many sesquiterpenes contain a pentacyclic lactone group and are therefore referred to as sesquiterpene lactones. These compounds occur abundantly in the family Asteraceae. Because of their bitter taste sesquiterpene lactones presumably serve as feeding deterrents of herbivores (Heinrich et al., 1998). Pharmacologically active sesquiterpene lactones often show anti-inflammatory effects due to inhibition of the transcription factor NF-kB that mediates immunological responses and inflammation (LyB et al., 1998). Sesquiterpenes with such activities occur, for example, in chamomile Matricaria recutita), one ofthe most popular medicinal plants. Antimigraine action of some sesquiterpene lactones, e.g., par-thenolide from feverfew (Tanacetum parthenium), is mediated by inhibition of platelet aggregation... 

Feverfew extract was shown to inhibit deposition, aggregate formation and spreading of platelets on collagen fibres [54]. Changes in membrane-cytoskeletal interaction leading to a change in expression of membrane receptors involved in these processes may explain this result. Feverfew extract was further able to protect the endothelial monolayer in rabbit aortas from perfusion injury and some reversible increase in cAMP levels in the aorta segments was found [55]. 

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