Toolkit / Psychopharmacology

Antipsychotic dose equivalents (chlorpromazine equivalents)

Add up one or more antipsychotics, oral or depot, and express the total load as chlorpromazine equivalents using the equivalent doses in the Maudsley Prescribing Guidelines. Useful for case presentations, audits and spotting high combined doses.

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Add each antipsychotic the patient takes. For tablets, enter the total dose per day; for injections, the dose per injection and how often it is given. Results update as you type.

    Equivalent doses used (Maudsley)

    First-generation: each dose ≈ chlorpromazine 100 mg/day
    DrugEquivalentRange in literature
    Chlorpromazine100 mg/dayReference
    Flupentixol3 mg/day2–3 mg/day
    Fluphenazine2 mg/day1–5 mg/day
    Haloperidol2 mg/day1.5–5 mg/day
    Pericyazine10 mg/day10 mg/day
    Perphenazine10 mg/day5–10 mg/day
    Pimozide2 mg/day1.33–2 mg/day
    Sulpiride200 mg/day133–300 mg/day
    Trifluoperazine5 mg/day2.5–5 mg/day
    Zuclopenthixol25 mg/day25–60 mg/day
    Flupentixol decanoate10 mg/week10–20 mg/week
    Fluphenazine decanoate5 mg/week1–12.5 mg/week
    Haloperidol decanoate15 mg/week5–25 mg/week
    Zuclopenthixol decanoate100 mg/week40–100 mg/week
    Second-generation: doses ≈ each other (risperidone 4 mg ≈ chlorpromazine 267 mg)
    DrugEquivalentNote
    Amisulpride400 mg/day
    Aripiprazole15 mg/day
    Asenapine10 mg/daysublingual
    Brexpiprazole2 mg/day
    Cariprazine1.5 mg/day
    Clotiapine100 mg/day
    Iloperidone12 mg/day
    Lumateperone21 mg/dayexpert consensus
    Lurasidone80 mg/day80 mg hydrochloride = 74 mg base
    Melperone300 mg/day
    Molindone50 mg/day
    Olanzapine10 mg/day
    Quetiapine400 mg/day
    Risperidone4 mg/day
    Sertindole10 mg/dayexpert consensus
    Ziprasidone80 mg/day
    Aripiprazole once-monthly injection300 mgper month
    Olanzapine pamoate405 mgper 4 weeks
    Paliperidone palmitate (monthly)100 mgper month
    Risperidone long-acting injection (Consta)50 mgper 2 weeks

    Notes

    • Equivalent doses are taken from the Maudsley Prescribing Guidelines. For first-generation antipsychotics, each listed dose is roughly equal to chlorpromazine 100 mg/day. For second-generation antipsychotics, the listed doses are roughly equal to each other (for example olanzapine 10 mg ≈ risperidone 4 mg ≈ quetiapine 400 mg).
    • Second-generation doses are converted to chlorpromazine through Maudsley’s statement that, very approximately, 100 mg chlorpromazine ≈ 1.5 mg risperidone. Comparisons between first- and second-generation drugs are therefore the least certain part of any total.
    • Clozapine is not included: Maudsley gives no equivalent because of its distinct titration, wide dose–plasma level variability and probably different mechanism. Blonanserin and xanomeline have no established equivalent yet, and penfluridol is not listed.
    • For injections, enter the dose given at each injection and choose the interval; the calculator converts it to an average daily load. Paliperidone 3-monthly and 6-monthly injections are not included.
    • These are rough guides for comparing and summing doses. They are no substitute for clinical titration against response and adverse effects when switching, and there is considerable disagreement between sources about exact equivalences.
    • Doses above licensed maximums, or combined antipsychotics, need a documented rationale and closer physical monitoring (ECG, metabolic, prolactin).

    References

    1. Taylor DM, Barnes TRE, Young AH. The Maudsley Prescribing Guidelines in Psychiatry. 15th ed. Wiley-Blackwell; 2025. Chapter 1, “Equivalent doses”, Tables 1.4 and 1.5.

    An educational aid for clinicians, not a substitute for clinical judgement. Check every result against the ECG, the drug chart and your local guidelines. Nothing you enter on this page is stored or sent.

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