In current study, efficacy of feverfew migraine prophylaxis in a randomized, double-blind, placebo-controlled was investigated of 60 migraine patients. From the analysis of the efficacy criteria, the MIDAS score, migraine intensity and frequency were reduced by extract of T. parthenium.
Of the 27 patients who completed the study, there was a 56.26% and 61.62% reduction in severity and frequency of migraine attacks during feverfew treatment, respectively. Regarding the safety of feverfew extract the incidence of side effects in the treatment group was similar to placebo. The effective dose for migraine headaches is 100 – 300 mg, standardized to contain 0.2 – 0.4% parthenolides (
16). Canada's Health Protection Branch granted a Drug Identification Number (DIN) recommends 125 mg per day of dried feverfew leaf containing at least parthenolide 0.2% for the prophylactic treatment of migraine (
17). In this study, the parthenolide content of the Iran cultivated feverfew was 0.4% that for migraine prevention is necessary.
Some studies showed feverfew might inhibit cytochrome P450 1A2 (CYP1A2) and increase the levels of drugs metabolized by CYP1A2 in humans. In present study, the patients used propranolol that metabolized by CYP450, so the level of propranolol might increase (
18,
19). Some of the observed improvement in patient headache may be due to the fact that propranolol serum level was higher in the feverfew group.
In some previous clinical trials, the effect of feverfew as a migraine prophylaxis was studied.(
10,
11) In one study in Germany, the results indicated that the extract of feverfew with a dosage of three capsules of 6.25 mg per day reduced the migraine attacks per month (
11). In a clinical trial, 72 migraine patients received dried feverfew leaves (82 mg) or placebo per day for four months. The frequency of migraine attacks in feverfew group was reduced 24%, furthermore nausea and vomiting in the migraine attacks was reduced, significantly (
10). In the other double-blind clinical trial, 17 migraine patients received feverfew leaves (50 mg/day) or placebo for 6 months. The frequency and severity of headache, nausea and vomiting in placebo group was increased while there was no change in the migraine frequency and intensity in feverfew group (
12). In a randomized clinical trial, the effect of a combination of riboflavin, magnesium and feverfew for prevention of migraine was investigated. The treatment group received drugs for three months. The results indicated a significantly reduction in frequency of migraine attacks but riboflavin 25 mg showed more effect than combination therapy (
20). The combination of feverfew and Salix alba was used for migraine prophylaxis for twelve weeks. The frequency and severity of migraine were reduced 61.7% and 62.6% at 12 weeks, respectively (
21). In present study, frequency and severity headache were reduced more than 50%.
Different limitations may have affected the findings of the study such as, the bitter taste of drug and low compliance by patients, small sample size and the positive effect of propranolol.
In conclusion, the extract of feverfew cultivated in Iran showed a significant migraine prophylactic effect with no adverse events. Accordingly, in a current clinical trial this effect is studied in 60 migraine patients with 2 - 8 migraine attacks per month for at least one year. In this study, patients used propranolol and some of the prophylactic effect may be due to the propranolol. The authors suggested to evaluation of feverfew without using propranolol. Because of the low number of patients, these findings need to be confirmed in a larger randomized controlled investigation. Because of the bad taste of feverfew drop is proposed to study the effects of feverfew in other dosage forms like capsule.