- Prescribing Advice for GPs - https://www.prescriber.org.uk -

Hypnotics and cancer risk concerns

New research published in the journal Sleep Medicine has raised concerns of an association between the use of hypnotics and an increased risk of cancer, in particular lung cancer. This study has been published in the wider media (Daily Mail and Daily Express).

This study connected data from the Finnish Public Sector study with the Finnish Cancer Register and the Drug Prescription Register of Finland. 5,053 cases of cancer were matched with 24,388 controls. Sex, age, socio-economic status, employer, and geographical area were used for matching. Purchases of prescribed sleep medications were used as an indicator of use of these medications.

Compared to non-use of sleep medications the odds ratio was 1.18 (95% CI 1.01-1.39) for those who used more than 100 defined daily doses per year and 1.16 (95% CI 1.01-1.34) for those who had such medication for more than three years. In cancers of the respiratory system the odds ratio for >100 defined daily doses per year versus no use was further raised at 3.47 (95% CI 1.97-6.11).

There are several limitations to this study; the data are observational, purchase of a prescription is presumed to be equivalent to use and there appears to have been no corrections made for smoking status.

The authors conclude that, "sleep medications use was associated with increased cancer incidence of the respiratory system". However they also state that, "further studies are needed to examine potential carcinogenic mechanisms".

Action: Clinicians should be aware of this study. There are already good reasons to limit use of these medicines to severe cases and for short durations of treatment. This study may be an opportunity to reduce use in patients who are on long term treatment and who are concerned about their cancer risk.