Levodopa-induced drowsiness in healthy volunteers: results of a choice reaction time test combined with a subjective evaluation of sedation.
The aim of the present study was to assess levodopa (L-Dopa)-induced drowsiness in healthy volunteers using two parameters: choice reaction time and a subjective rating of sedation. Sixteen subjects participated in a randomized, double-blinded, crossover study. A single dose of 200 mg L-Dopa or placebo was administered at 9:00 AM. To limit peripheral side effects connected with L-Dopa, subjects were treated with 20 mg domperidone three times daily. Subjective rating of sedation consisted of visual analogue scale. Reaction time was measured by means of responses to two light-emitting diodes. The illumination of one of these diodes constituted the imperative signal. Manual responses were performed on two buttons located under the right and left index fingers. Results demonstrated a positive correlation between sedation level and reaction time (r = 0.70, p = 0.0026). Adverse events of L-Dopa were nausea (four cases) and excitation (one case). Subjects who did not develop adverse events were faster under L-Dopa than under placebo (p = 0.02), whereas subjects who had nausea or excitation were slower. A single dose of L-Dopa either deteriorated or improved choice reaction time in healthy volunteers according to whether it was sedative and whether it generated disruptive adverse events.
Micallef-Roll
J
J
Centre de Pharmacologie Clinique et d'Evaluations Thérapeutiques et Service de Pharmacologie Clinique, Université Mixte de Recherche, Hôpital de la Timone, Marseille, France.
Rihet
P
P
Hasbroucq
T
T
Possamaï
C
C
Blin
O
O
D000328:Adult; D000978:Antiparkinson Agents / Q000494:pharmacology*; D016009:Chi-Square Distribution; D002755:Choice Behavior / Q000187:drug effects* / Q000502:physiology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D011930:Reaction Time / Q000187:drug effects* / Q000502:physiology; D012894:Sleep Stages / Q000187:drug effects* / Q000502:physiology
D000978:Antiparkinson Agents; D006993:Hypnotics and Sedatives; D007980:Levodopa