A study of tolerance to the psychomotor effects of indomethacin in healthy volunteers.

We have examined the effect of single dose indomethacin 50 mg on objective measurements of psychomotor function and whether this effect is altered by pretreatment with indomethacin 25 mg t.i.d. for 7 days in 10 healthy volunteers (5 male, 5 female; age 20-54 y). One hour after a single dose of indomethacin 50 mg there was significant impairment of psychomotor function (critical flicker fusion frequency threshold and choice reaction time) (Wilcoxon p less than 0.05). Pretreatment with indomethacin 25 mg t.i.d. for 7 days prevented this impairment. Thus we conclude that tolerance occurs over the course of a week to the psychomotor effects of indomethacin.