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Keywords:

  • adverse drug reaction;
  • drug;
  • memory;
  • pharmacoepidemiology;
  • pharmacovigilance

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

• Iatrogenic amnesia is one of the main aetiologies of transient amnesia.

• Benzodiazepines and anticholinergic drugs are considered to be the drugs most often responsible for iatrogenic amnesia.

• The impact of drugs in memory disorders is particularly pronounced in elderly people, especially due to polymedication.

WHAT THIS STUDY ADDS

• An association between memory disorders and some drugs, such as benzodiazepines, antidepressants and older anticonvulsants, was found as expected.

• A strong association was found with unexpected drugs, such as benzodiazepine-like hypnotics (zopiclone and zolpidem), serotonin reuptake inhibitor antidepressants and newer anticonvulsants.

• Non-neurotropic drugs, such as isotretinoin and ciclosporin, were also associated with memory disorders.

AIMS To investigate putative associations of reports of memory disorders and suspected drugs.

METHODS We used the case/noncase method in the French PharmacoVigilance Database (FPVD). Cases were reports of memory loss in the FPVD between January 2000 and December 2009. Noncases were all other reports during the same period. To assess the association between memory impairment and drug intake, we calculated an odds ratio with its 95% confidence interval.

RESULTS Among the 188 284 adverse drug reactions recorded, we identified 519 cases of memory loss. The sex ratio was 0.6 and the median age was 54 years (range 4–93). The maximal number of cases occurred between 40–49 and 50–59 years. Evolution was favourable in 63% of the cases. We found significant odds ratios for benzodiazepines (alprazolam, bromazepam, prazepam, clonazepam etc.), benzodiazepine-like hypnotics (zolpidem and zopiclone), antidepressants (fluoxetine, paroxetine and venlafaxine), analgesics (morphine, nefopam and tramadol), anticonvulsants (topiramate, pregabalin, levetiracetam etc.), antipsychotics (aripiprazole and lithium) and other drugs, such as trihexyphenidyl, ciclosporin and isotretinoin.

CONCLUSIONS Our study confirmed an association between memory disorders and some drugs, such as benzodiazepines and anticonvulsants. However, other drugs, such as benzodiazepine-like hypnotics, newer anticonvulsants, serotonin reuptake inhibitor antidepressants, isotretinoin and ciclosporin were significantly associated with memory disorders, although this was not described or poorly described in the literature.

Taking account of the limits of this study in the FPVD (under-reporting, notoriety bias etc.), the case/noncase method allows assessment and detection of associations between exposure to drugs and a specific adverse drug reaction, such as memory disorders, and could thus generate signals and orientate us to further prospective studies to confirm such associations.