[Effect of fentanyl, diazepam and flunitrazepam on memory function. A pharmacopsychologic study]

This study was designed to differentiate possible amnesic effects of diazepam, flunitrazepam and fentanyl into impairment of storage, retention or retrieval of information and to correlate them with alterations in a vigilance task. 4 groups of 7 volunteers each were studied in a double-blind, random fashion. They performed a quasi continuous word recognition task i.e. after a preload list of 150 words played on a tape they had to indicate if the following words (grouped into 10 blocks of 100 words each) were new ones or had occurred already. Interposed were measurements of reaction time to a visual stimulus, and of concentration and short-time memory. During the experiment, unknown to the test person, diazepam 10 mg/70 kg, flunitrazepam 1 mg/70 kg, fentanyl 0.15 mg/70 kg or placebo were infused over 3 min. For evaluation of the word recognition task the d' index drawn from signal detection theory was employed. The results clearly indicated that both benzodiazepines specifically impair memory function the effect of flunitrazepam being more pronounced and longer in duration. Since retrieval of information learnt before administration of either drug was completely unaffected it was concluded that both drugs specifically influence encoding and registration of information. Reaction times were not significantly altered after diazepam, whereas they were prolonged by more than 50% after flunitrazepam indicating a pronounced sedative action of this drug. However, even during this period of maximal effect of flunitrazepam, recognition of words first presented prior to injection was not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)