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Chlorpromazine equivalents and percentage of British National Formulary maximum recommended dose in patients receiving high-dose antipsychotics

Author(s) :

Graeme Yorston and Alison Pinney

Abstract :

The study compared two methods of identifyingpatientsprescribedhigh doses of antipsychotic medication among in-patients and out-patients in Buckinghamshire. High doses were definedasthoseinexcessof1000 mg chlorpromazine equivalents CPZE) per day or more than100% of the maximum recommended dose in the British National Formulary BNF).

A total of 258 patients were identified as being prescribed antipsychotics, 30 of whom receivedhighdoses.Therewas 93% concordance between the two methods for identifying these patients. Nine of the 12 patients whohadbeenprescribedhigh potency R1000 mg CPZE/day) but low toxicity R100% BNF maximum) therapy were receiving flupenthixol decanoate. A group of six high-risk patients were identified who had been prescribed lower potency drugs at supra-maximal doses.

Expressing total antipsychotic dose as a percentage of the BNF maximum is easy to understand and calculate. It helps to ensure patients at risk of antipsychotic toxicity are easily identified to ensure monitoring guidelines can be followed.

Psychiatric Bulletin 2000), 24,130-132 - Source link

Collège Méditerranéen de Psychiatrie