Intramuscular drug regimens for acute severe behavioural disturbance in adults

Managing a patient with acute behavioural disturbance is a detailed flowchart for managing a patient with acute behavioural disturbance.

The indications for intramuscular sedation for acute severe behavioural disturbance in adults are detailed here.

Most emergency departments and hospitals have protocols for the safe use of parenteral sedation—follow local protocols or consensus state guidelines where available. If intramuscular sedation is used, monitor the patient closely for adverse drug effects. For information about minimum monitoring and equipment requirements, see Principles of monitoring patients with acute behavioural disturbance. In community settings (especially in rural and remote areas) if the minimum monitoring and equipment requirements are not available, a senior clinician needs to make a risk assessment of the situation proportionate to the risk of the sedative drug.

The aim of pharmacological management is to calm the patient with a sufficient initial dose of a sedative drug. Repeated subtherapeutic doses that are inadequate to reduce the patient’s distress and calm their behaviour can prolong the risk of harm to the patient or others. This can also result in larger cumulative doses, or multiple drug administration, both of which increase the risk of adverse drug effects.

The most common drugs used in adults to manage acute severe behavioural disturbance are benzodiazepines and antipsychotics, which are used in this setting for their sedative effects. The sedative effects of antipsychotic drugs occur much sooner than the antipsychotic effects. If the patient has had a previous paradoxical reaction to benzodiazepines, or is tolerant to benzodiazepines, avoid benzodiazepines.

When selecting a suitable dose and regimen for a sedative drug, consider patient factors, such as their level of agitation and distress (eg measured with a Sedation Assessment Tool [SAT] score), age, body size, sex, comorbidities, drug history, previous response to sedative drugs and response to treatment.

If intramuscular sedation is indicatedfor an adult with acute severe behavioural disturbance, in combination with nonpharmacological techniques, use:

The SAT score can be used to determine whether sedation has been effective, or a repeat dose is needed. Individualise the target SAT score based on patient factors (eg response to nonpharmacological interventions, whether the patient needs to be sedated for investigations) and the ability to maintain patient and staff safety. Rarely, when immediate control of the situation is required and the chosen regimen (above) has failed to achieve control, rescue sedation  can be considered.

If droperidol or olanzapine are not accessible, haloperidol may be used as an alternative to droperidol, at the same dose range; however, haloperidol is less effective than the drugs recommended above and may cause significant extrapyramidal adverse effects and QT-interval prolongation with risk of arrhythmias. Intramuscular chlorpromazine is not recommended as a sedative drug for this indication as it causes hypotension.

Rarely, when immediate control of a life-threatening situation is required, emergency intramuscular ketamine sedation can be used first line for rapid sedation. This is only applicable in extreme circumstances and under instruction from a senior clinician.

If an adult patient is being physically restrained to facilitate pharmacological management, continue restraint until a clinical response to the sedative is apparent (ie the patient is calm but rousable). Titrate any additional doses of intramuscular sedative drugs with caution because people who are restrained are more susceptible to adverse effects.

Always monitor the patient closely for potential adverse effects after administering an intramuscular sedative drug.