MANY FREQUENTLY prescribed sleeping tablets are linked with an unexplained increased risk of death and a higher likelihood of developing cancer.
The increased risk arises even among those taking fewer than 18 doses of sleeping tablets a year.
The findings are a result of a large-scale study involving more than 34,000 people carried out by researchers in the US.
While the researchers stress their study does not prove cause and effect for harm arising when using these drugs, the increased risk of both death and the development of cancer are demonstrably higher.
The findings are published this morning in the online British Medical Journaltitle, BMJ Open. The authors tracked the survival of more than 10,500 people who were prescribed a range of sleeping tablets between 2002 and 2007. These were compared with more than 23,500 matched controls who did not receive any sleeping tablets.
The researchers found clear differences between the two groups. Those receiving between 18 and 123 doses a year were four times as likely to die than the controls, and those taking more than 123 doses faced a five-fold increased risk of death.
Yet even those taking less than 18 doses a year were 3.5 times more likely to die, the authors found. The patients in the study “had approximately 4.6 times the hazard of dying over an average observation period of 2.5 years as compared to non-users”, they write.
Those taking the higher number of doses were also 35 per cent more likely to be diagnosed with cancers of some sort.
Drugs examined in the study included benzodiazepines such as temazepam; non-benzodiazepines such as zolpidem, eszopiclone and zaleplon; barbiturates and finally sedative antihistamines.
All of these have been prescribed in Ireland, although benzodiazepines and barbiturates are much less likely to be prescribed today, one pharmacist said yesterday. Sleeping tablets are frequently dispensed here however.
Between 6 and 10 per cent of US adults used sleeping tablets during 2010, according to a US study. This means sleeping tablets could have been associated with between 320,000 and 507,000 excess deaths in the US alone, the authors calculate.
The authors believe it may be time to think again about alternatives to sleeping tablets for the treatment of insomnia.
They also question whether safety guidelines for these drugs need to change.