Careful consideration of drug treatment is a critical part of delirium assessment and treatment.  Drug administration or abrupt withdrawal are both causes of delirium (see Medicines optimisation).  

Non-pharmacological practices should be tried before pharmacological interventions are considered. Causes of distress and agitation, such as pain, urinary retention, constipation, thirst, should be addressed first. 

There is insufficient evidence available to support recommendations on the efficacy and safety of pharmacological therapies for patients with delirium.  

Expert opinion suggests there is a role for medication in specific situations, such as patients in intractable distress, and where the safety of the patient and others is compromised. In these circumstances the SDA pathway suggests starting one of these medications on the lowest dose, and reviewing every 24 hours: 

  • haloperidol 0.5-1mg orally (max 2mg/24 hours)  
  • haloperidol 0.5mg IM (max 2mg/24 hours)  

(Haloperidol is contra-indicated in combination with QTc prolonging drugs, which makes it unlicensed and local “off label” policy should be followed).

  • Or atypical antipsychotic at low dose, for example, risperidone 0.25mg daily, maximum 1mg in 24 hours  

Do not use if signs of Parkinsonism or Lewy body dementia  

If antipsychotics are contra-indicated (as above): 

  • lorazepam 0.5-1mg orally (max 2mg/24 hrs) 
  • midazolam 2.5mg IM (max 7.5mg/24 hours).  

Younger patients may need higher drug doses. 

See the evidence base in section 7, SIGN 157 here

Scottish Delirium Association Management Pathway

Further expert opinion on pharmacological treatments in older patients is available in the British Geriatrics Society Good Practice Guide.