Ashtons’ antipsychotic dosage and percentage calculator
Ashtons has recently produced a new handy antipsychotic dosage and percentage calculator. The guide offers an easy way to calculate the percentage BNF values of each antipsychotic. The chart is presented in an easy-to-use table form in alphabetical order, of the most commonly used antipsychotics and their most frequently used doses. The chart includes antipsychotics in oral, intramuscular, long acting and depot formulations. The values are calculated as daily doses for oral/IM medication and weekly doses for long acting/depot antipsychotics. We have also included a guide to calculating cumulative doses.
There are three primary reasons for the importance of these values:
- To understand the combined values and identify if high dose antipsychotic monitoring is required, i.e. if the cumulative dose of the antipsychotics prescribed are above 100% BNF limit.
- To maintain within the required legal requirements where the MHA documentation specifies a specific BNF upper limit.
- To help understand comparative BNF percentages of different antipsychotics, which can prove useful during switches and augmentation of antipsychotics. Please note it may be useful to also refer to the Maudsley guidance for first-generation or second-generation antipsychotic equivalent doses (pages 14 and 15 in The Maudsley Prescribing Guidelines in Psychiatry, 13th edition, by David Taylor et al) to assist with switching.
As Clopixol Acuphase (zuclopenthixol acetate) has its own unique way to calculate the BNF cumulative dose (doses given within a two-week period), we have also provided a useful guide to assist you with this specific treatment.
As a reminder, high dose antipsychotic monitoring is recommended as per the Royal College of Psychiatrists high-dose antipsychotic treatment consensus (CR190), The Maudsley Guidelines and NICE clinical guideline (CG178) for psychosis and schizophrenia in adults: prevention and management. To assist you with complying with this monitoring requirement, Ashtons has a useful, recently updated ‘High Dose Antipsychotic Monitoring Form’ (HDAT1). This can be ordered free of charge via the Ashtons online ordering system or by contacting customer services on 0345 222 3550 or firstname.lastname@example.org
Your visiting pharmacists will circulate A4 poster versions of the chart for each ward, and we have also created A5 versions to circulate to clinicians at sites. If you have not yet received a personal copy, please be sure to let your visiting pharmacist or customer services know, and we will be happy to provide you with additional copies.