Certain medications for insomnia have been shown to impair driving performance the morning after they are taken. These medications are valium-like compounds called benzodiazepines. However, Rozerem (ramelteon) has not been shown to impair driving the next day. There is a study in the Journal Sleep about the effect of ramelteon on driving performance that I found rather interesting.
Researchers studied 30 healthy volunteers without insomnia. They gave them a dose of zopiclone (similar to Lunesta but not approved for use in the United States), a dose of ramelteon, and a placebo dose on three separate nights. They picked zopiclone because prior studies have shown it can impair driving the next day. Researchers and subjects did not know which pill they were getting each night. They let the patients sleep 7.5 hours and then tested their driving ability on an actual road, as opposed to a driving simulator. They also tested their balance 1.5 hours after taking the pill, meaning they had to be woken up after falling asleep. Finally, they gave them a battery of thinking, memory, and motor tests the morning after they took each pill.
The results showed no serious adverse effects occurred. The most common ones were decreased attention, sleepiness, and fatigue. Contrary to what was expected, ramelteon significantly impaired driving performance, thinking, and memory tests the next morning. Zoplicone did as well, but this was expected. Ramelteon's affect on driving was as strong as having a blood-alcohol concentration of 0.05%, which has been shown to impair driving. The legal limit in most states is 0.08%.
The authors conclude that patients taking ramelteon should be cautioned about driving, since they could experience impairment on the morning after taking it.