Choice of long-acting injectable antipsychotic for recovery and relapse prevention in adults and young people

When starting a long-acting injectable antipsychotic, it is preferable to use an antipsychotic that the patient has tolerated in oral form and, ideally, has responded to and is stabilised on (ie taken for at least 2 weeks). This:

  • reduces the risk of a persistent intolerable adverse effect
  • makes switching easier and more accurate (if the patient is stabilised on the antipsychotic)
  • increases the chance the patient will respond to the long-acting injectable formulation (if they have responded to the oral antipsychotic).
If the patient takes an oral antipsychotic not available as a long-acting injectable formulation, to establish tolerability, first switch to an oral antipsychotic that is available as a long-acting injectable formulation (see Approximate equivalent oral and long-acting injectable dosages for some antipsychotics). There is limited head-to-head evidence to guide long-acting injectable antipsychotic choice—consider adverse effect profiles.

Olanzapine is second-line therapy because it causes significant cardiometabolic adverse effects, and the long-acting injectable formulation rarely causes a postinjection syndrome with signs and symptoms consistent with olanzapine overdose. If using the long-acting injectable formulation of olanzapine monitor for signs of sedation every 30 minutes for at least 2 hours after the injection, or until the patient is alert and oriented and free from signs or symptoms of overdose.

When offering a long-acting injectable antipsychotic formulation, if possible, discuss the following with the patient and, if the patient consents, their family, carers or significant others:

  • the purpose of the antipsychotic and its place in multifaceted treatment
  • advantages and disadvantages of a long-acting injectable formulation compared to an oral formulation
  • the importance of treatment adherence—advise the patient that poor adherence is the largest single cause of relapse, especially in young people with a recent-onset disorder
  • if switching antipsychotics, which antipsychotic adverse effects are acceptable to the patient and how these effects are monitored, prevented and addressed.

Ensure adequate follow-up is arranged between doses. Patients with underlying treatment resistance, comorbid disorders of substance use, and personality disorders may have a greater risk of relapseCorbeil 2022, and may require more frequent follow-up between doses.

For additional considerations in antipsychotic choice, see: