Coadministered Benzodiazepines
As with anticholinergics, the prophylactic coadministration of benzodiazepines has been traditionally recommended with the intent of preventing or reducing recovery reactions. A single controlled trial in ED adults found that midazolam pretreatment (0.03 mg/kg IV) significantly reduced the incidence of recovery agitation by 17% (number needed to benefit: 6). Unfortunately, this study failed to describe the nature or severity of these reactions, and so it remains unclear how many of the events were clinically important and how many were minor and transient. Nevertheless, midazolam prophylaxis appears a reasonable but nonmandatory option in adults.
In children, however, 2 controlled trials and a large meta-analysis have failed to note even a trend toward benefit from such prophylaxis. Children have far fewer recovery reactions than adults, and thus the routine pretreatment of such patients is not supported by the evidence. When unpleasant ketamine-associated recovery reactions do rarely occur, they can be rapidly and reliably diminished with titrated benzodiazepines.