Experimental and clinical psychopharmacology
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Exp Clin Psychopharmacol · Jun 2010
Randomized Controlled Trial Clinical TrialDifferential effect of codeine on thermal nociceptive sensitivity in sleepy versus nonsleepy healthy subjects.
Basal sleepiness-alertness modulates drug effects. Sleepiness produced by sleep restriction leads to increased nociceptive sensitivity, suggesting opioid analgesia may also be modulated by sleepiness-alertness. This study compared thermal nociceptive sensitivity in sleepy versus nonsleepy participants after codeine or placebo. ⋯ More important, there was a Group x Drug interaction with codeine increasing FWL in the nonsleepy, but not the sleepy, group. These data show the analgesic effects of codeine are diminished in sleepy versus nonsleepy individuals. They suggest clinical differences in response to analgesics are partly explained by basal state of sleepiness-alertness.