It is not uncommon that patients may need to be switched from one antipsychotic to another. Chlorpromazine equivalents help guide clinicians in estimating an approximately equivalent dose when transitioning from one antipsychotic to another.

How should I convert doses between different antipsychotics?1-8

Antipsychotic Dose Equivalents (based on chlorpromazine equivalents)

Generic Brand Dose Equivalent
First Generation Antipsychotics
Chlorpromazine Thorazine© 100 mg
Fluphenazine Prolixin© 2 mg
Haloperidol Haldol© 2 mg
Loxapine Loxitane© 10 mg
Perphenazine Trilafon© 8 mg
Pimozide Orap© 2 mg
Prochlorperazine Compazine© 15 mg
Trifluoperazine Stelazine© 2-5 mg
Thioridazine Mellaril© 100 mg
Thiothixene Navane© 4 mg
Second Generation Antipsychotics
Aripiprazole Abilify© 7.5 mg
Asenapine Saphris© 4 mg1
Brexpiprazole Rexulti© N/A
Cariprazine Vraylar© N/A
Clozapine Clozaril© 100 mg
Iloperidone Fanapt© 3-4 mg1
Lurasidone Latuda© 16 mg1
Olanzapine Zyprexa© 5 mg
Paliperidone Invega© 2 mg1
Quetiapine Seroquel© 75 mg
Risperidone Risperdal© 1 mg
Ziprasidone Geodon© 60 mg


Long acting injectable antipsychotic IM Equivalents

Based on: Rothe PH, Heres S, Leucht S. Dose equivalents for second generation long-acting injectable antipsychotics: The minimum effective dose method. Schizophr Res. 2018;193:23-8.

Antipsychotic Long Acting Injection Minimum Effective Dose
Aripiprazole lauroxil  (Aristada) 441mg (300mg of aripiprazole) every 4 weeks
Aripiprazole microspheres (Abilify Maintena) 400mg every 4 weeks
Haloperidol decanoate (Haldol Decanoate) 50mg every 4 weeks
Olanzapine pamoate (Zyprexa Relprevv) 210mg every 2 weeks
Paliperidone palmitate (Invega Sustenna) 25mg every 4 weeks
Risperidone microspheres (Risperdal Consta) 25mg every 2 weeks
Risperidone suspension  (Perseris) 90mg every 4 weeks


Minimum effective dose defined as the lowest fixed dose from at least one double blind randomized control trial which demonstrated consistent superior efficacy over placebo.4


  1. Leucht S, Samara M, Heres S, Patel MX, Woods SW, Davis JM. Dose equivalents for second-generation antipsychotics: the minimum effective dose method. Schizophrenia Bulletin. 2014;40(2):314-26. DOI: 10.1093/schbul/sbu001. PubMed PMID: 24493852; PubMed Central PMCID: PMC3932104.
  2. Leucht S, Samara M, Heres S, Davis JM. Dose Equivalents for Antipsychotic Drugs: The DDD Method. SCHBUL. 2016;42 Suppl 1:S90-4. DOI: 10.1093/schbul/sbv167. PubMed PMID: 27460622; PubMed Central PMCID: PMC4960429.
  3. Rothe PH, Heres S, Leucht S. Dose equivalents for second generation long-acting injectable antipsychotics: The minimum effective dose method. Schizophrenia Res. 2018;193:23-28. DOI: 10.1016/j.schres.2017.07.033. PubMed PMID: 28735640.
  4. Leucht S, Samara M, Heres S, Patel MX, Furukawa T, Cipriani A, et al. Dose Equivalents for Second-Generation Antipsychotic Drugs: The Classical Mean Dose Method. Schizophr Bull. 2015;41(6):1397-402. DOI: 10.1093/schbul/sbv037. PubMed PMID: 25841041; PubMed Central PMCID: PMC4601707.
  5. Patel MX, Arista IA, Taylor M, Barnes TRE. How to compare doses of different antipsychotics: a systematic review of methods. Schizophr Res. 2013;149(1-3):141-8. DOI: 10.1016/j.schres.2013.06.030. PubMed PMID: 23845387.
  6. Taylor D, Paton C, and Kapur S. The Maudsley Prescribing Guidelines in Psychiatry, Wiley-Blackwell; 11th Edition, 2011.
  7. Schatzberg AF, Cole JO, and DeBattista C. Manual of Clinical Psychopharmacology, American Psychiatric Publishing; 7th Edition, 2010.
  8. Woods SW. Chlorpromazine Equivalent Doses for the Newer Atypical Antipsychotics. J. Clin. Psychiatry. 2003;64(6):663- 667. DOI: 10.4088/JCP.v64n0607. PubMed PMID: 12823080.