• sedation;
  • cognition;
  • human psychopharmacology


Two studies were undertaken to investigate the sedative and congnitive effects of cyclobenzaprine (Flexeril®) in volunteers, using a computerized battery of congnitive tests and subjective rating scales. In Study 1 the effect of acute administration of two doses of cyclobenzaprine (2.5, 5 mg orally) were compared with a single dose of diphenhydramine (Benadryl; 50 mg orally) and placebo. On most tests diphenhydramine produced a significant impairment compared to placebo, whereas there were typically no significant differences between cyclobenzaprine and placebo. In Study 2 the effects of repeated dosing with cyclobenzaprine (5 mg three times daily for 10 doses) were compared to placebo. The test battery was administered after the fourth and tenth doses. There was a small but mainly nonsignificant trend for subjects receiving cyclobenzaprine to do worse at the first test session. No differences between treatments were apparent by the second test session. The battery of tests used here would appear to be useful for assessing sedation. © 1992 Wiley-Liss, Inc.