Olanzapine is prescribed in the treatment of schizophrenia and BPAD. It is not licensed for personality disorders, behavioural issues or in patients with opiate addiction.This audit sought to identify the number of opiate dependent patients in a tertiary referral centre on olanzapine and the reason why.

All patients attending one sector had their notes examined over a three year period to see whether they are or were on olanzapine. All patients were opiate dependent and prescribed methadone.Parameters looked at included Axis 1 or 2 diagnosis, previous psychiatric in-patient admissions, forensic history and whether fasting lipids and glucose were checked.

169 charts were reviewed.Of these, 37 patients either were on or had been on olanzapine (21.9% overall).20 of these patients (11.8%) had an Axis 1 disorder, 17(10%) had behavioural diffciulties.Of the 20 patients with an Axis 1 disorder, 18 of them had an in-patient hospital admission.Only 7 of 17 patients on olanzapine with behavioural issues had an in-patient admission.All patients with behavioural difficulties had a forensic history and 16/17 had custodial sentences.15 of the 20 patients with Axis 1 diagnoses served custodial sentences.

A significant percentage of patients were prescribed olanzapine off license with no clinical indication.This is a worrying finding due to the abuse potential of olanzapine and longer term metabolic effects.Caution should be taken with prescribing olanzapine to opiate addicts who abuse it for its sedative effect.The value of this study is that it is one of the few to date to describe this problem.