The elderly are more prone to the adverse effects of benzodiazepines because of:
- Reduced capacity to metabolise benzodiazepines as well as reduced renal excretion. This may result in accumulation of the drug.
- Increased sensitivity to the effects of benzodiazepines (unrelated to pharmacokinetic changes).
In particular, the elderly are at greater risk of:
- Memory impairment
- Impaired cognitive function
- Poor psychomotor performance
- Falls, which might result in injury, such as hip fracture
- Behaviour disinhibition—often manifesting as irritability and argumentativeness
It is likely that many long-term users of benzodiazepines are elderly.
Factors which increase risk
Frailty increases the risk of harm from benzodiazepine adverse effects; in addition to weakness, reduced function of various body organs and systems can further contribute to complications.
Many elderly people receive several medicines (‘polypharmacy’); this raises the potential for interaction with benzodiazepines, thereby increasing the risk of excessive sedation, respiratory and cardiovascular impairment, and mental effects such as confusion.
Having established that a benzodiazepine is essential for treatment, the initial dose in the elderly should generally be half the usual adult dose.
A short-acting benzodiazepine should be chosen for the elderly to reduce the possibility of accumulation and consequent side effects.
With support and encouragement, it may be possible to help elderly long-term users of benzodiazepines to come off them and benefit from reversal of reduced mental acuity and memory.
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