Principles of antipsychotic use

Antipsychotics have been classified in different ways (eg typical and atypical, first generation and second generation), but these classifications are not pharmacologically meaningful and are not used in these guidelines.

The dose of antipsychotic required to achieve the best balance of effectiveness and adverse effects varies considerably between individuals. Using higher than recommended doses rarely improves symptoms but is associated with an increased risk of adverse effects. However, a psychiatrist may exceed the recommended dose range in patients with treatment-resistant schizophrenia, and increased doses of olanzapine (up to 30 mg daily) may be used for short-term treatment of agitation.

Combining antipsychotics increases the risk of adverse effects. Only use only one antipsychotic at a time unless:

• switching between antipsychotics
• temporarily augmenting long-acting injectable antipsychotic therapy in a patient with breakthrough symptoms (ie while the long-acting injectable antipsychotic reaches a therapeutic concentration)
• under psychiatrist direction.

If a patient uses more than one antipsychotic, seek specialist advice about transitioning to monotherapy; this may not always be possible for patients with psychotic disorders.

For additional information on antipsychotic use, see:

• Antipsychotic use in females of childbearing potential
• Antipsychotic use during pregnancy
• Antipsychotic use while breastfeeding.