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Letter to the Editor

Editor, – Thank you to Dr Caplan for the excellent and timely review of the management of delirium in the elderly (Aust Prescr 2011;34:16-8). Benzodiazepines (diazepam in particular) are the treatment of choice for delirium tremens in Australia. I would like to point out that benzodiazepines can at times be the cause of delirium.

Midazolam, diazepam, triazolam, lorazepam and clonazepam have all been reported to cause confusion, agitation, aggression and disinhibition in the very young and elderly. This is the so-called 'paradoxical reaction' from benzodiazepines.

Paradoxical reaction has been reported as a rare condition in the normal population. However, past reports suggest that its incidence is significant in certain populations such as intensive care patients and postoperative elderly patients, particularly elderly people with risk factors for delirium, as pointed out by Dr Caplan.

I have encountered a number of elderly patients given diazepam for alcohol withdrawal who have developed confusion, agitation and on rare occasions hallucination. The most severe cases are those managed by inexperienced resident medical officers who have mistaken the presentations with delirium tremens. The patients were given cumulatively large doses of diazepam as a result and their condition deteriorated further. It is a reminder to us all that the elderly can be more at risk of adverse reactions to medications, and often conservative measures as listed by Dr Caplan should be the treatment of choice.

Raymond Chan
Addiction medicine physician
Dandenong Hospital, Vic.

Author's comments

Dr G Caplan, author of the article, comments:

I thank Dr Chan for his kind words. There is no doubt that cumulatively large doses of benzodiazepines, as well as antipsychotics, will frequently exacerbate delirium in older patients. Dosing schedules for young patients with psychosis or delirium may act as a recipe for disaster in older patients. There is also evidence from a small randomised controlled trial in young AIDS patients that lorazepam is not an effective treatment for delirium and perhaps makes things worse. However the comparators, haloperidol and chlorpromazine, were effective,1 as antipsychotics have been in other trials.

Because of the hazards of drug interactions and adverse effects, initial management should always focus on stopping drugs that may be aetiological.