Overview of disorders of quetiapine and other antipsychotic use

Concern is growing about the use of some antipsychotics, particularly quetiapine, for indications that are not approved by the Australian Therapeutic Goods Administration (TGA). Quetiapine is being prescribed more often, using low doses for unapproved indications, because of its anxiolytic properties and the perception that it is safer than benzodiazepinesBrett, 2020Hollingworth, 2010. However, quetiapine and other antipsychotics have long-term adverse effects and the potential for nonmedical use. Nonmedical use of quetiapine describes use that does not align with the directed useAustralian Institute of Health and Welfare (AIHW)McNeely, 2014. For example, a person may use quetiapine to treat a symptom other than the clinician directed, or to become intoxicated. Most nonmedical use of quetiapine is oral, but there are reports of intranasal use, especially in prisonsHaysom, 2020, and of it being smokedVento, 2020. At the time of writing, there have also been limited reports of nonmedical use of the antipsychotic, olanzapine. Sedating properties increase the likelihood of nonmedical antipsychotic use.

Quetiapine toxicity can result in sedation, respiratory depression, seizures, cardiovascular effects and anticholinergic toxidrome. For advice on assessment and management of toxicity from quetiapine and other antipsychotics, see Antipsychotic drug poisoning.

Check real-time prescription monitoring programmes before prescribing quetiapine1; olanzapine is not currently included in these programmes. Consider staged supply (dispensing small amounts of medication [eg daily, second daily or weekly]) if nonmedical use is considered likely.

The spectrum of substance use is described in these guidelines by the terms ‘hazardous use’, ‘harmful use’ or ‘substance dependence’, outlined in Terminology describing the spectrum of substance use. Quetiapine and other antipsychotic dependence can manifest as withdrawal after abruptly stopping the drug (following use as prescribed or nonmedical use).
1 At the time of writing, real-time monitoring of quetiapine is required in some jurisdictions only.Return