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4.2.1 Antipsychotic drugs

Prescribing Notes

Antipsychotics for the treatment of schizophrenia should be initiated by a psychiatrist. Contact appropriate psychiatric services.
  • Do not start antipsychotic medication for a first presentation of sustained psychotic symptoms in primary care unless it is done in consultation with a consultant psychiatrist
  • Modified release(MR) preparations of quetiapine should be reserved for patients with compliance issues
  • Some patients may be suitable for switching to quetiapine immediate release once stabilised on quetiapine MR
  • Clozapine is the drug of choice for treatment resistance. It requires monitoring and is a red list drug that should not be prescribed in primary care. However, it is important that clinically important medication such as clozapine is added to the patient’s record. Method varies depending on GP clinical system e.g. add the drug as ‘issued but not printed’ or enter drug source as ‘issued outside the practice or secondary care’. See Specialist Medicines Supplement from January 2019 for further information
  • Clozapine and olanzapine are metabolised principally via CYP1A2 therefore clearance is increased in smokers. People who stop or reduce their smoking may require a dose reduction. Refer to SPS website or further details.
  • For patients taking clozapine who are intending to stop smoking, specialist advice should be sought to ensure the patient’s safety
  • GPs and other primary healthcare professionals should monitor the physical health of people with psychosis or schizophrenia when responsibility for monitoring is transferred from secondary care, and then at least annually.

Maintenance treatment

  • Patients should remain on the antipsychotic which controlled their symptoms unless symptoms return or side-effects are intolerable; the dose should be monitored and reviewed regularly with specialist advice and over time might be reduced
  • Specialist advice should be sought before discontinuing antipsychotics due to the risk of relapse. Current evidence states that patients presenting with first episode of acute functional psychosis should ideally remain on antipsychotics for a minimum of one year


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