Psychotropic medicines are frequently dosed outside recommended ranges: a clinical audit in an Australian mental health hospital

Background

Compliance with psychotropic dosage guidelines has been shown to improve mental health status, reduce severity of symptoms, and decrease adverse effects. However, guideline recommendations are not always implemented. While deviation from dosage recommendations may be clinically appropriate in some patients, variation can cause a lack of efficacy or patient harm.

Aim

To evaluate the incidence of antidepressant and antipsychotic prescribing at doses outside the recommended range provided by local guidelines, Therapeutic Guidelines: Psychotropic.

Method

This study is a retrospective clinical audit of 793 patients admitted to hospital between August 2018 and July 2019. Data were collected through extensive file and chart reviews of patients treated with any of the antidepressant and antipsychotic medications listed in the Psychotropic Dosage Guidelines. Descriptive statistical analyses were performed to determine frequencies and proportions.

Results

The audit identified that 38.0% of patients received doses of antidepressants or antipsychotics outside the recommended range. Most antidepressants were prescribed within recommended doses (83.0%), with 10.5% above the recommended dose, and 6.2% below. Fewer antipsychotics were prescribed within the recommended range (56.8%), 2.8% were prescribed at doses above the recommended range, and 40.3% were prescribed at doses below the recommendation range. Quetiapine was frequently prescribed at doses lower than recommended.

Conclusion

The audit revealed a substantial amount of prescribing outside the recommended dosage ranges. It also highlighted the necessity of reviewing policies to limit the use of off-label, low-dose quetiapine. Audit and feedback could target psychiatrists who seem to have the highest propensity to prescribe outside the recommended dosage ranges.