Statin-associated memory loss: analysis of 60 case reports and review of the literature.

OBJECTIVE: To review case reports of statin-associated memory loss as well as the available published evidence for and against such a link.
METHODS: We searched the MedWatch drug surveillance system of the Food and Drug Administration (FDA) from November 1997-February 2002 for reports of statin-associated memory loss. We also reviewed the published literature (using MEDLINE) and prescribing information for these drugs.
RESULTS: Of the 60 patients identified who had memory loss associated with statins, 36 received simvastatin, 23 atorvastatin, and 1 pravastatin. About 50% of the patients noted cognitive adverse effects within 2 months of therapy. Fourteen (56%) of 25 patients noted improvement when the statin was discontinued. Memory loss recurred in four patients who were rechallenged with the drug. None of the 60 reported cognitive test results. Two placebo-controlled trials found no benefits for statins on cognition or disability. One randomized controlled trial of simvastatin found no effects on cerebrospinal amyloid levels. In one small, randomized study, patients receiving statins showed a trend toward lower cognitive performance than those receiving placebo. Five observational studies found a lower risk of dementia among patients receiving statins.
CONCLUSION: Current literature is conflicting with regard to the effects of statins on memory loss. Experimental studies support links between cholesterol intake and amyloid synthesis; observational studies indicate that patients receiving statins have a reduced risk of dementia. However, available prospective studies show no cognitive or antiamyloid benefits for any statin. In addition, case reports raise the possibility that statins, in rare cases, may be associated with cognitive impairment, though causality is not certain.