Ketamine Better than Haloperidol for Sedation Onset But Not Much Else

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It is not uncommon to deal with highly agitated patients in healthcare, especially the elderly, who are the most susceptible to alterations of mental status.  Individuals can become confused, disoriented and agitated for a variety for a reasons and can pose serious harm to themselves as well as to the care provider.

A new study, published in the journal Clinical Toxicology, reveals how the party drug ketamine, has proven itself to be far more effective at sedating combative patients prior to hospitalization than haloperidol, which is commonly used.  Ketamine is generally used as a pre-operative anesthetic for surgeries that do not require skeletal muscle relaxation.  It inhibits the brain from perceiving painful sensations.  It is often referred to as a “dissociative anesthetic,” (similar to PCP), which distorts the user’s perception of sight and sound, producing feelings of detachment from the environment and oneself. Ketamine has a rapid onset of action without affecting the airway (as seen with benzodiazepines) and it has a wide therapeutic index - making it an attractive drug to study for acute, undifferentiated agitation.

Clinician researchers from Minneapolis conducted two trials over six-month periods where for three months haloperidol was given and then alternated with ketamine for three months throughout an entire calendar year.  There were a total of 146 subjects, 64 of whom received ketamine and 82 were given haloperidol.  These subjects, who were being transported to area hospitals, had their mental status evaluated by emergency medical responders trained to use the Altered Mental Status Scale (AMSS).

What the results showed were that those individuals who received ketamine took an average of five minutes to achieve sedation compared with 17 minutes with haloperidol.  Although this was a promising finding, it was concerning that 49 percent of the ketamine group had markedly increased complications compared to five percent in the haloperidol group.  Additionally, 39 percent of the ketamine group required intubation (a breathing tube) compared with four percent with haloperidol.

These subjects were not randomized and this was not a blinded study. Therefore, the data are subject to confounding factors such as the patient’s status at baseline, the type of injury/illness or if the patient had consumed something that negatively interacted with ketamine (an excess of 80 percent of patients were picked up for drug and/or alcohol intoxication).  There was a hesitation on the part of paramedics to obtain informed consent and enroll patients for participation when ketamine was the only sedative option, which inadvertently contributed to a selection bias.

This study encourages further research into the favorable aspect of achieving rapid onset sedation.  Perhaps with dosing adjustments, or in conjunction with another therapy, safer formulations could be developed.