Lirequinil is a benzoquinolizinone derivative. It is a partial agonist to the benzodiazepine (BDZ) receptor. Lirequinil slightly lowered the rhythmic slow-wave activity frequency during waking mobility. Lirequinil acts more selectively than nitrazepam to promote the drowsy EEG pattern, and the partial agonistic properties may minimize the residual effects during waking mobility similar to the short-acting agent zopiclone. Lirequinil was well tolerated at all doses, causing no clinically relevant changes in vital signs or laboratory parameters. At doses of 10 and 30 mg there were signs of unsteady gait, indicating a central nervous system depressant effect. Lirequinil had been in phase II for the treatment of sleep disorders.