WEDNESDAY, Aug. 13, 2014 (HealthDay News) -- Many shift workers take drugs to sleep or stay awake despite lingering questions about their benefits and risks, researchers report.
The study authors analyzed the findings of 15 clinical trials that included a total of 718 people. Nine of the trials found that the over-the-counter hormone drug melatonin helped shift workers sleep about 24 minutes longer during the night or day, but did not help them get to sleep quicker.
One study looked at the hypnotic drug zopiclone, and found that it was no more effective than an inactive placebo at helping shift workers sleep during the day.
The other five studies assessed the effects of caffeine and the drugs modafinil and armodafinil, which are prescribed for sleepiness during night shifts. Caffeine reduced sleepiness during night shifts when workers also took naps before shifts, the investigators found.
Modafinil and armodafinil did boost alertness and reduce drowsiness, but caused headaches, nausea and increased blood pressure in many shift workers, according to the Cochrane Reviews.
In many developed countries, at least 10 percent of workers do some type of shift work.
"For lots of people who do shift work, it would be really useful if they could take a pill that would help them go to sleep or stay awake at the right time," review author Juha Liira, of the Finnish Institute of Occupational Health in Helsinki, said in a Cochrane news release.
"But from what we have seen in our review, there isn't good evidence that these drugs can be considered for more than temporary use and some may have quite serious side effects," the researcher noted.
"It's curious that there's such a clear gap in the research," said Liira. "It may well be that studying the effects of these drugs or other drugs in properly designed trials would be seen as unethical because workers should not need drugs to get along with their work. So the studies just haven't been done or if they have, our review has not been able to identify relevant data."
The American Psychological Association outlines the risks of shift work.