Abstract: We identified only two trials that satisfied the selection criteria. We did not pool the data because of the substantial clinical differences between the trials. In one trial, participants (n = 58) were patients in an acute palliative care unit with advanced cancer who had a mean age of 64 years. All of the participants had delirium, were treated with haloperidol, and were randomised to receive either lorazepam or placebo in combination with it. Due to very serious imprecision, all evidence was of low certainty. We were unable to determine whether there were clinically important differences in the severity of delirium (mean difference (MD) 2.10, 95% CI -0.96 to 5.16; n = 50), length of hospital admission (MD 0.00, 95% CI -3.45 to 3.45; n = 58), mortality from all causes (risk ratio (RR) 0.33, 95% CI 0.04 to 3.02; participants = 58) or any of a number of adverse events. Important effects could not be confirmed or excluded. The study authors did not report the length of the delirium episode. In the other trial, participants (n = 30) were patients in general medical wards with acquired immune deficiency syndrome (AIDS) who had a mean age of 39.2 years. Investigators compared three drug treatments: all participants had delirium, and were randomised to receive lorazepam, chlorpromazine, or haloperidol. Very low-certainty evidence was identified, and we could not determine whether lorazepam differed from either of the other treatments in the effect on severity of delirium, any adverse event, or mortality from all causes. The study authors did not report the length of the delirium episode or the length of hospital admission. There is no enough evidence to determine whether benzodiazepines are effective when used to treat patients with delirium who are cared for in non-ICU settings. The available evidence does not support their routine use for this indication. Because of the scarcity of data from randomised controlled trials, further research is required to determine whether or not there is a role for benzodiazepines in the treatment of delirium in non-ICU settings.

Plain-language summary: We found only two small studies which were suitable to include in our review. In one study, the 58 patients who took part all had advanced cancer. They were treated in a specialist palliative care unit. The study compared lorazepam (a benzodiazepine) to placebo. In the second study, the 30 patients all had AIDS (acquired immune deficiency syndrome). They were treated in general medical wards. This study compared lorazepam to two different drugs that are sometimes used to treat delirium. We did not find any important benefits for patients who took lorazepam instead of the other treatment in these two studies. Patients who took it did not have better outcomes. We do not have any definite evidence that lorazepam was more harmful than the other treatment, but, in the study of patients with AIDS, the researchers stopped treating people with lorazepam after the first six people who took it all had serious side effects. Because there were only two suitable studies and both had small numbers of patients in them, we cannot draw any firm conclusions. Currently, there is no good evidence to tell us whether or not benzodiazepines should be used to treat patients with delirium. Clinicians, patients, and carers should be aware of the lack of evidence. We think there is a need for more research, and particularly for studies that involve older patients in general medical and surgical settings, where most delirium is treated.