ABSTRACT
The benzodiazepines and “Z” drugs impair anterograde memory (i.e., amnesia for events that occur after taking the drugs). They do not commonly produce a significant effect on retrograde memory (i.e., amnesia for events that have already occurred before taking the drugs). The selective anterograde amnesic effect is used to advantage in the perioperative setting in order to reduce any unpleasant memories, but this amnesic effect is undesired in most other circumstances. Although the effect can occur in any patient, it can be magnified in sensitive patients and older patients, because age-related changes in pharmacokinetics can reduce the metabolism and elimination of these drugs. Benzodiazepines and their metabolites can then accumulate, leading to intensified problems. But even a patient who has been prescribed a benzodiazepine for an approved indication in a dose that appears to be safe, can experience severe memory loss or confusion after several doses, since many benzodiazepines are eliminated from the body relatively slowly, and because they accumulate in fatty tissues due to their lipid solubility. As a result, even a patient taking a typical standard dose may suffer a significant memory loss after a short course of therapy. If the therapy is extended beyond 2–4 weeks, the patient may have significant difficulties not only during the course of therapy, but sometimes for long periods after discontinuation of therapy.
