Neil V. Marrion, PhD
Professor of Neuroscience
Programme Director for BSc and MSci Pharmacology degrees
School of Physiology & Pharmacology
Medical and Veterinary Sciences University Walk
University of Bristol Bristol, BS8 1TD.
MedicalResearch.com: What are the main findings of the study?
Dr. Marrion: We tested pravastatin and atorvostatin (two commonly prescribed statins) in rat learning and memory models. Rats were treated daily with pravastatin (brand name – Pravachol) or atorvostatin (brand name – Lipitor) for 18 days. The rodents were tested in a simple learning task before, during and after treatment, where they had to learn where to find a food reward. On the last day of treatment and following one week withdrawal, the rats were also tested in a task which measures their ability to recognise a previously encountered object (recognition memory).
The study’s findings showed that pravastatin tended to impair learning over the last few days of treatment although this effect was fully reversed once treatment ceased. However, in the novel object discrimination task, pravastatin impaired object recognition memory. While no effects were observed for atorvostatin in either task.
MedicalResearch.com: Were any of the findings unexpected?
Dr. Marrion: Between six and seven million people in the UK take statins daily and the findings follow anecdotal evidence of people reporting that they feel that their newly prescribed statin is affecting their memory. Last year, the US Food and Drug Administration (FDA) insisted that all manufacturers list in their side effects that statins might affect cognitive function. However, probably the most surprising finding is that not all statins display this effect on cognitive function.
MedicalResearch.com: What should clinicians and patients take away from your report?
Dr. Marrion: It is important to emphasize that the therapeutic use of statins is established and extremely beneficial to those who are at risk of atherosclerosis and stroke. However, the anecdotal evidence suggests that a significant minority of these patients will be affected by this side effect. It is clear that patients should seek expert advice from their GP if they experience unwanted cognitive side effects, as it is possible that another statin might be more suitable.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Dr. Marrion: This study used the two most commonly used statins, but at a fixed high dose. It is clear that more commonly prescribed statins should be tested, using the range of clinically prescribed doses. Importantly, the mechanism of how coginitive function might be impaired has to be elucidated to permit understanding of why some statins do and some do not exhibit this side effect.
Chronic Pravastatin but Not Atorvastatin Treatment Impairs Cognitive Function in Two Rodent Models of Learning and Memory’ by Stuart SA, Robertson JD, Marrion NV, Robinson ESJ is published in PLOS ONE : e75467. doi:10.1371/journal.pone.0075467