Statins may cause sleep disorders
December 17, 2007 By Cafer Zorkun, M.D. Ph.D. 
According to results of a study from the University of California at San Diego School of Medicine evaluating the non-cardiac effects of statins, a daily dose of 20 mg simvastatin was associated with significantly worse sleep quality than 40 mg pravastatin daily or placebo.
The study evaluated 1,016 subjects for sleep quality and sleep problems at baseline and at six months. Participants were adult males over age 20 or post-menopausal females with LDL cholesterol levels of 115-190 mg/dL and no known cardiovascular disease or diabetes mellitus. Study participants had not used statins before.
On a sleep-quality scale of 0-30, (30 being best), participants rated simvastatin at 14.67 after six months, versus 15.79 for pravastatin and 15.50 for placebo. On a sleep-problem scale of 0-2, 2 being much worse, participants rated simvastatin at a mean of 0.213 versus pravastatin at 0.098 and placebo at 0.074 (p-values for the sleep-problem comparisons were 0.015 for simvastatin versus placebo, 0.093 for simvastatin versus pravastatin and 0.464 for pravastatin versus placebo).
Subjects who reported “much worse sleep” while taking simvastatin also showed a significant adverse change in aggression scores compared with others in the trial.
One of the principal investigators and leading author Dr Beatrice A. Golomb said “Sleep problems can affect quality of life and may have adverse health consequences, such as promoting weight gain and insulin resistance”. She also pointed out that although the average effect of simvastatin on sleep was detrimental, this does not mean that everyone on simvastatin will experience worse sleep.
Dr. Golomb said a “much better” rating for sleep problems was reported half as often for simvastatin versus placebo, while a “much worse” sleep problem rating was reported 2.7 times as often for simvastatin versus placebo. Simvastatin users exhibited significantly worse subjective sleep, relative to either placebo or to pravastatin, despite comparable sleep ratings at baseline.
Dr. Golomb said. “This provides tentative corroboration for longstanding concerns that lipophilic statins may affect sleep in some individuals.” Dr. Golomb concluded that "lipophilic simvastatin may penetrate cell membranes and cross the blood brain barrier, allowing it to interfere with sleep more easily than hydrophilic pravastatin".