Doctors are calling for reconsideration of the use of sleeping pills after a study revealed that the drugs carried a substantially increased risk of death for those who are prescribed them.
Commonly used sleeping pills or “hypnotics” such as Temazepam and Zolpidem, which are prescribed for short-term insomnia, are associated with more than a fourfold risk of death, according to the study published in the online open-access journal BMJ Open.
The study was carried out in the United States, where up to 10% of the adult population took sleeping pills in 2010. The authors estimate that sleeping pills may have been associated with 320 000 to 507 000 extra deaths in the US that year.
The researchers, led by Daniel Kripke from the Scripps Clinic Viterbi Family Sleep Centre in La Jolla, California, studied the population served by the largest rural integrated healthcare system in the US, in Pennsylvania.
Over a two-and-a-half-year period they compared the death rates among more than 10 500 people who received sleeping pill prescriptions with those of more than 23600 others – matched for age, state of health and other factors — who had not received such medication. The average age of the group was 54.
The scientists in the study found that even at a relatively low rate of prescription, fewer than 18 doses a year, those who were given the pills had a 3.5 times greater risk of death compared with those who were not prescribed them.
Individuals who were given pills more frequently — between 18 and 132 doses in a year — were more than four times more likely to be dead by the end of the study. The risk of death for those on the most pills — 132 doses or more a year — was more than five times that of those not taking pills.
Those who had taken the most pills were also 35% more likely to be diagnosed with cancer — although they had not been at greater risk of cancer than the control group before the study began.
Just showing an association between sleeping pills and more deaths does not prove the pills are the cause, the authors say, although the increased risk as the number of doses went up points in that direction. But there have been other studies that have also appeared to detect an increased death risk with sleeping pills.
Some US doctors have suggested a randomised controlled trial to establish for certain the death risk of sleeping pills, they write.
“No such trial has ever been mounted, perhaps for reasons similar to the absence of randomised trials of cigarettes and of skydiving without parachutes.” Yet the benefits of sleeping pills “as critically reviewed by groups without financial interests” are meagre, they add, and it is now generally thought that cognitive behaviour therapy works better for people with chronic insomnia than tablets.
The doctors say there are many ways in which sleeping pills might shorten life. Such medication has been shown to increase depression, which can trigger suicide. They also interfere with motor and cognitive skills, which makes driving dangerous and can cause sleep apnoea, which can lead to heart problems.
Some people taking the pills sleepwalk, which can be hazardous, and eat at night, “resulting in poor diet and obesity”, says the paper.
In the study, people on sleeping pills were more likely to have oesophageal problems and peptic ulcers. They were more likely to be diagnosed with lymphomas, lung, colon and prostate cancers than even smokers.
The National Institute for Health and Clinical Excellence has given qualified approval to the short-term use of sleeping pills. The authors suggest it may be time to reconsider even that limited green light.
Nina Barnett of the Royal Pharmaceutical Society said it was “an important study and although it is unlikely to radically change prescribing in the immediate term, it should raise awareness and remind both patients and prescribers to the potential risks of sedative use for insomnia”.
The Medicines and Healthcare Products Regulatory Agency said the safety of all medicines on the United Kingdom market was continuously monitored.
It added: “Hypnotics should be used to treat insomnia only when it is severe, disabling, or subjecting the individual to extreme distress and use should be restricted to a short term of two to four weeks.” —