the evening) of the plasma corticosteroid levels. Amphetamines may interfere with urinary steroid determination. Headache (26%), asthenia (6%), somnolence , infection , tooth disorder , speech disorder , and twitching have also been reported. REFERENCE + Stimulant medications precipitate Tourette's syndrome. Lowe TL, Cohen DJ, Detlor J, Kremenitzer MW, Shaywitz BA JAMA