Sedative effects and impaired learning and recall after single oral doses of lorazepam.
Seven healthy subjects received oral placebo, 1.5 mg lorazepam, or 3.0 mg lorazepam in a single-dose, three-way crossover study. Plasma lorazepam concentrations and subjects' self-rated sedative effects were evaluated at multiple points during 24 hours after each dose. Information acquisition and recall was studied by use of a 16-item word list at 3 and 24 hours after dosing. Lorazepam plasma concentrations were proportional to dose. Self-rated sedation was maximal 2 to 3 hours after lorazepam dosing, persisted for 8 hours, and was dose dependent in intensity; no significant sedation occurred with placebo. At 3 hours after placebo dosing, subjects learned a mean 96% of words presented during six trials; this was reduced to 79% and 62% after lorazepam, 1.5 and 3.0 mg, respectively (F = 6.2; P less than 0.02). Twenty-four hours after placebo, subjects recalled 92% of words presented the previous day, then improved to 99% after six relearning trials. After 1.5 and 3.0 mg lorazepam, however, only 52% and 44% of words were initially recalled from the previous day. Thus single oral doses of lorazepam within the therapeutic range produce dose-dependent sedation and impairment of information acquisition and recall.
R I
RI
Shader
D
D
Dreyfuss
J R
JR
Gerrein
J S
JS
Harmatz
S J
SJ
Allison
D J
DJ
Greenblatt
D000284:Administration, Oral; D002849:Chromatography, Gas; D005260:Female; D006801:Humans; D007858:Learning / Q000187:drug effects*; D008140:Lorazepam / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*
D008140:Lorazepam