in a double-blind crossover trial of two 12-week treatment periods with a 4-week treatment free interval , to which 21 patients were admitted , there was no statistically significant difference between clonidine 75 microgram twice daily and placebo in the total number of headache days , migraine indices , duration of attacks , number of severe attacks and consumption of acute attack treatment .
C0018681
headache
C0149931
migraine