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Antipsychotic Dose Load

AP_Load2026 calculatorreference table 2026

Each prescribed daily dose as a percentage of a documented reference dose, summed across agents without an upper cap. Clozapine is referenced to a target individualised for sex and cigarettes per day; the other antipsychotics to a fixed dose reconciling the WHO DDD and the licensed maximum.

Patient

Sex

Tobacco only. Induction of CYP1A2 saturates at about ten cigarettes a day, so e-cigarettes, nicotine replacement and heated-tobacco products count as zero.

Clozapine anchors

The standard configuration tracked measured plasma clozapine better; the alternative is provided for reproducing published comparisons, not as an equivalent option.

Regimen

Add as many antipsychotics as the regimen has; the load is their sum, uncapped. Doses are mg/day for oral agents and mg per injection interval for depots.

AP_Load2026

— % of reference
DDD / day
—
% BNF maximum
—
Agent Ref. AP_Load DDD/d %BNF
Total — — — —

Reference doses

The dose that scores 100. Oral agents are reconciled as the geometric mean of the licensed maximum and the WHO DDD, capped at 1.5 × DDD; injectables are referenced to the licensed maximum for the same dosing interval; clozapine to an individualised target, shown here for the sex and consumption set above.

Agent BNFmax WHO DDD AP_Load = 100 Basis

A research normalisation of prescribed dose, not a prescribing or regulatory instrument.

Fernandez-Egea E, Krishnadas R, Jenkins C, Patel R, Cardinal RN, Wolpe N. The Antipsychotic Dose Load (AP_Load2026): a normalised prescribed-dose index for schizophrenia research.

Reference implementations in Python, R and SPSS, and the complete dated reference tables, accompany the paper.