In most developed countries, at least one out of 10 workers does some form of shift work. Unsurprisingly, shift workers take drugs to help them stay awake or get to sleep, yet there’s both a lack of research of the drugs most commonly used by shift workers and often only weak evidence of benefit, according to the authors of a new review.

In fact, the over-the-counter and prescription drugs commonly used by shift workers might do more harm than good for some people. “It's curious that there's such a clear gap in the research," said Dr. Juha Liira, of the Finnish Institute of Occupational Health in Helsinki and lead author of the review. "It may well be that studying the effects of these drugs or others 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."

What is Shift Work Disorder?

Shift Work Disorder affects some people who work at night or frequently rotate shifts. Because these schedules go against the body's natural circadian rhythm, many people have difficulty adjusting to a new sleep and wake pattern. The sleep interruption that results may in turn cause difficulty sleeping or excessive sleepiness. Disturbances to normal sleeping and waking patterns increase the risk of accidents and affect shift workers' health. In jobs where shift work cannot be avoided — including health care, the police force, or the military — drugs can potentially offer short-term benefits and prevent accidents.

For the review, the researchers located 15 trials involving a total of 718 people in the literature. Most of these trials were too small to be of real value, plus most tended to be carried out in specific settings, such as an oil rig. Would their results be relevant for workers in other jobs? In nine of the studies, the over-the-counter hormone drug melatonin helped shift workers sleep for around 24 minutes longer during the night or day, compared to placebos. However, melatonin did not help anyone get to sleep more quickly. Another study tested the hypnotic drug zoplicone but found it to be no more effective than placebos in helping shift workers sleep on command.

The remaining studies focused on caffeine and two drugs prescribed for alertness: modafinil and armodafinil. Caffeine reduced sleepiness during night shifts, but only when workers also napped before shifts. In separate trials, modafinil and armodafinil were found to increase alertness and reduce sleepiness as desired. However, a substantial number of participants also suffered headaches, nausea, and a rise in blood pressure.

"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," Liira said. Unfortunately, the results of this review suggest some may have serious side effects, while others should only be used for a short period. There’s no short cuts when trying to break from your natural rhythm.