One of the most widely prescribed drug classes is made up of chemical compounds known as “statins.” Millions of prescriptions are written for these drugs every year. They are typically prescribed as a treatment for high cholesterol and serum lipid levels. They appear to be quite effective for these uses and have been shown to reduce heart attack risk, as well. Unfortunately, in some cases they have undesirable side effects including muscle pain and liver damage. Recently, the medical community has become interested in potential negative effects on memory, especially short-term memory loss. This article briefly discusses these issues.
Memory is a function of the central nervous system, specifically the brain. In order for any substance to affect memory it must be able to cross the “blood brain barrier.” That is, it has to be able to leave the bloodstream and reach the neural tissues where memory processes take place. Statin drugs are able to cross this barrier. Some do so more easily than others.
Cholesterol is a necessary component for proper functioning of the nervous system. It must be present in order for memories to be created, stored and retrieved. Any agent that reduces the cholesterol in the nervous system below the proper threshold has the potential to diminish memory function. Ideally, we would like for Statin medications to work effectively in the bloodstream but to have minimal effect in the nervous system.
Simvastatin, for example, appears to be the Statin that most easily moves from the bloodstream into the brain. Pravastatin has much less ability to cross the blood brain barrier. This tells us that any affect on the central nervous system from a Statin drug will presumably be stronger with Simvastatin than it is with Pravastatin, including short-term memory loss.
The website Medscape recently completed a major study to investigate whether Statin drugs affect memory. The researchers found numerous complaints related to memory loss while taking statins. Some subjects even reported amnesia. There was common agreement that memory loss always reversed when the statins were discontinued. There was no indication of cause and effect between statins and memory loss. All of the evidence is based on reports from the subjects.
As mentioned above, cholesterol is a necessary component for proper functioning of the nervous system. However, Alzheimer’s disease has been related to excessive cholesterol. Autopsies have shown that elderly individuals who had taken statin drugs showed fewer signs of Alzheimer’s disease than those who did not. Like most processes associated with the human body, the proper balance is the key to good health. A concentration of cholesterol within the nervous system that is too low may be associated with short-term memory loss. However, a concentration that is too high may be associated with dementia. Drugs that interfere with these cholesterol levels may have the ability to unbalance the system.
In summary, negative memory affects have been reported that people associate with taking statin drugs. In any case, the problems seem to disappear when the medication is discontinued. People who are taking statins such as Simvastatin may want to discuss the possibility of substituting another statin, one which does not cross the blood brain barrier so easily. As we age it is increasingly important to disclose any changes in mental as well as physical functioning. Memory loss can have many causes and should be thoroughly discussed with a physician.