What is Restoril (Temazepam)? Restoril (temazepam) is a benzodiazepine (ben-zoe-dye-AZE-eh-peen). Temazepam affects chemicals in the brain that may be unbalanced in people with sleep problems (insomnia). Restoril is used to treat insomnia symptoms, such as trouble falling asleep or staying asleep. Restoril works by slowing down the central nervous system (brain), causing drowsiness which helps patients fall asleep.