Sleepless? Maybe it's your statin

Last Updated: 2007-11-07 11:44:01 -0400 (Reuters Health)

CHICAGO (Reuters) - A popular drug used to keep cholesterol in check might be interfering with a good night's sleep, U.S. researchers said on Wednesday.

A large study looking at sleep patterns of people who took the statin drug simvastatin, sold under the trade name Zocor, found they had significantly worse sleep quality compared with people who took pravastatin, sold under the trade name Pravachol, another cholesterol-lowering drug.

"The findings are significant because sleep problems can affect the quality of life and may have adverse health consequences, such as promoting weight gain and insulin resistance," Dr. Beatrice Golomb, of the University of California at San Diego School of Medicine, said in a statement.

She presented her study at the American Heart Association meeting in Orlando, Florida.

While both simvastatin and pravastatin help lower levels of low-density lipoprotein (LDL), the so-called "bad" cholesterol, simvastatin is lipophilic, meaning it is soluble in fats, while pravastatin is hydrophilic, meaning it is soluble in water.

Because simvastatin is fat soluble, it can more easily penetrate cell membranes, making its way across the blood-brain barrier, a mechanism that protects the brain from infection.

Golomb wanted to see if this difference explained why some people on statins reported having trouble sleeping.

She studied more than 1,000 healthy adult men and women for six months. Study participants received simvastatin, pravastatin or placebo.

Their sleep quality was recorded on two different sleep rating scales.

"The results showed that simvastatin use was associated with significantly worse sleep quality," Golomb said.

She said the study suggests people who are having insomnia while taking simvastatin should consult their doctor.