Statins linked to disturbed sleep
Statins have been found to cause major sleep problems in a significant proportion of patients. Simvastatin, taken by around two million patients in the UK, is particularly associated with insomnia, nightmares and other sleep disorders, new research concludes.
The finding, presented at the American Heart Association's annual scientific conference this week, questions assumptions that the main statins are broadly equivalent in adverse events.
It also has a significant implications for UK drug switching policy, under which GPs are coming under increasing pressure from PCTs to move patients on to Simvastatin.
The study presented results of a trial of over 1,000 patients.
Simvastatin use was associated with significantly worse sleep quality, and significantly more sleep problems, such as insomnia or nightmares, than either pravastatin or placebo.
The trial compared 1,016 people without coronary artery disease or diabetes, but who did have a cholesterol level between 2.98 and 4.92 mmol/l. Patients were prescribed either simvastatin 20mg, pravastatin 40, or a placebo, for six months.
Sleep disturbances were assessed using an evaluation questionnaire called the Leeds sleep scale, which rated the severity of the sleep problems the patients experienced.
There was on average an 8-10% reduction in sleep quality compared with baseline in patients on simvastatin. Some 5% of patients characterised their sleep loss as the more severe possible on the scale.
There was no significant difference between the sleep quality or amount of sleep disturbance caused in patients in the pravastatin and placebo groups – suggesting effects of statins on sleep disturbance might be restricted to simvaststatin alone.
Study leader Dr Beatrice Golomb, associate professor of medicine at the University of California San Diego school of medicine, said the simvastatin-specific effect was likely to be related to the fact that it is the most fat soluble of the statins – meaning simvastatin may cross the blood barrier into the brain and penetrate the cells that control sleep regulation. By contrast, pravastatin is the least fat soluble of the statins.
Dr Golomb said there was a need for caution in deciding whether to switch patients en masse from one statin to another. ‘There are adverse events associated with statins, as well as benefits. I think it's important to consider harm as well as benefits of statins when governments are making widescale public health recommendations.'Simvastatin in particular was linked to sleep disturbance Simvastatin in particular was linked to sleep disturbance