The Cholesterol-Lowering Statin Drugs and Memory Loss

In the October 2005 issue of the Canadian Adverse Reaction Newsletter, 19 case reports of memory loss or impairment associated with the use of a cholesterol-lowering statin drug were analyzed. The statin drugs marketed in the U.S. are atorvastatin (LIPITOR), fluvastatin (LESCOL), lovastatin (MEVACOR), pravastatin (PRAVACHOL), rosuvastatin (CRESTOR), and simvastatin (ZOCOR).

In these 19 cases, the onset of memory impairment occurred within one month of starting a statin in five individuals, within one year in seven, and after one year in three cases. The date of onset was not reported in four cases. Eleven reports indicated that the memory problem resolved or improved when the statin was discontinued or the dose of the drug was reduced. One report said that memory problems returned after treatment with a statin was reinitiated.

The median age of statin-treated patients in whom memory problems were reported was 70 years and ranged from 50 to 78 years of age.

The professional product labeling for all statin drugs sold in the U.S. except for rosuvastatin mention memory impairment as a possible adverse effect. The professional labeling for atorvastatin indicates that in clinical trials conducted before the drug was approved, amnesia was reported in less than two percent of patients. Memory impairment is listed in the professional labeling for pravastatin as occurring in less than one percent of patients in clinical trials conducted before the drug was approved.

Pharmacists and physicians from the Duke University Medical Center reported in the July 2003 issue of the journal Pharmacotherapy that between November 1997 and February 2002, there were 60 adverse drug reaction reports involving a statin drug and memory loss made to the FDA. In 36 of these cases, simvastatin was the statin involved, atorvastatin accounted for 23 reports, and in one report pravastatin was the statin in question.

In these 60 reports, the patients’ average age was 62 years and ranged from 30 to 84 years. In thirty of the 60 reports documented both the time that statin treatment was started and the appearance of memory impairment. The median time for a memory problem to appear was two months.  

In 33 of the 60 cases, the statin was stopped after the appearance of memory impairment. Of these 33 patients, memory impairment resolved or improved in 14 cases when the statin was stopped. Memory loss recurred in four patients when statin treatment was restarted.

Published studies have suggested that statin treatment can contribute to memory impairment. In theory, this may happen because of cholesterol’s essential role in the production of the material that forms a coating around nerves called myelin. The statin drugs may enter the brain and decrease the amount of central nervous system cholesterol available to produce myelin, leading to a loss of the myelin coat that may cause memory problems.

Potentially, statin-induced memory impairment could be mistaken for other conditions such as early Alzheimer’s disease. This could result in the prescribing of a drug to treat Alzheimer’s when it is not needed.

What You Can Do

If you are taking a statin drug and you notice memory problems, talk to your doctor about stopping the drug or reducing the dose.