Provigil, as the drug is known in the US and Britain, is approved for treating the daytime sleepiness associated with the rare condition called narcolepsy, which makes people fall asleep involuntarily. But last week, the drug's manufacturer, Cephalon of West Chester, Pennsylvania, announced results from a clinical trial of 209 shift workers that showed it helps those with "shift work sleep disorder"- excessive sleepiness caused by odd working hours.
The trial is part of Cephalon's attempt to expand the range of conditions Provigil can be used for. Ultimately, the company hopes it can be prescribed to treat sleepiness that results from any medical condition, and plans to submit data from this and other trials for approval for such use to the US Food and Drug Administration (FDA) this year.
But critics fear that this could lead to the use of Provigil being extended from those with sleep disorders to healthy people who are simply sleep-deprived. While experts differ as to whether shift work sleep disorder is a real medical condition, it is clearly caused by lifestyle. Police, hospital staff, pilots and people who work at all-night stores are among the countless groups of workers likely to be affected. Get the drug approved to treat such people and the decision whether to treat those who are simply working or playing too hard becomes a distinctly grey area.
Some fear there would then be little to stop Provigil becoming the elixir of choice for the 24/7 generation. Several sleep researchers told New Scientist that patients with demanding careers and lifestyles are beginning to ask for Provigil to help them stay alert as they burn the midnight oil. "It's happening already," says Thomas Scammell, a sleep expert at the Beth Israel Deaconess sleep disorders clinic in Boston.
The clinical trial on shift workers is the latest of a string of studies showing how Provigil could benefit different groups of people. One study of military helicopter pilots showed that the drug helped them stay alert and capable of performing complex tasks for almost two days without sleep. Other studies have shown the drug seems to help patients with multiple sclerosis cope with fatigue. Ongoing trials are now looking at the drug's effect on tired truck drivers, medical staff and soldiers.
That the drug works so well is no surprise, as previous studies have shown it to be a potent stimulant. How it produces prolonged alertness is not well understood, but it is thought to act specifically in the brain's pre-frontal cortex. This is one of the most active areas of the brain in people who are awake, governing planning, memory and what we pay attention to.
The drug's localised effect may explain why it increases wakefulness without triggering the "wired" feeling of stimulants such as coffee and amphetamines. Surprisingly, tests also found that when the drug wore off, there was no noticeable need for an extended sleep to recover.
Critics of more widespread use of Provigil fear that the drug might give people a false sense that they can cheat their need for sleep, while in reality they may be accumulating a sleep debt that will ultimately harm them. Sleep deprivation leads to cognitive impairment, as well as seriously disrupting the immune and hormone systems, although it is not known how long these effects last. And Paul Blake of Cephalon acknowledges Provigil's limitations: "The drug isn't a replacement for sleep," he says.
On the other hand, Provigil could help prevent accidents common among shift workers, and make a big difference to soldiers on sustained operations or rescue workers at a major emergency. "It's an interesting challenge for society and for the FDA," says Neil B. Kavey, director of the Sleep Disorders Center at Columbia-Presbyterian Medical Center in New York. "We have to make sure nobody's going to get hurt," he says.
Written by SYLVIA PAGAN WESTPHAL, BOSTON
New Scientist issue 2nd November 2002
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