Studies investigating or controlling for the impact of antipsychotic medications often need to quantify the amount of medication to which an individual is or has been exposed. As different antipsychotics have different potencies, the task is more complicated than using each medication’s daily dosage in milligrams, for example.
chlorpromazineR is an R package to calculate dose equivalents for common oral and injectable antipsychotic medications based on conversion factors from the published literature. We do not propose to suggest which conversion factors are appropriate to use, or how to interpret the converted data. All users should also refer to the papers from which the conversion factor data originates to determine whether the use of such data is appropriate for their study.
We hope that this package is of use to scientists who do clinical research involving antipsychotic medications. Specifically, the goals of this package are:
For further details and usage, please see the walkthrough vignette.
This results from this package should be double checked for accuracy when used in production. We welcome feedback–please contact via [email protected] or file an issue.
The CRAN release version (recommended) can be installed via the command:
The development version of this package can be installed via the command:
Once installed, load package with
library(chlorpromazineR). The package’s main conversion functions are documented and usage and examples can be seen with
help(to_ap). It is strongly recommended to read the articles from which the keys are derived, and to verify that the program’s output is producing results as expected. This package facilitates bulk conversion, but should be verified to ensure it produces the results as expected.
An online calculator using this package is available as a shiny app.
participant_ID <- c("P01", "P02", "P03", "P04") age <- c(42, 29, 30, 60) # not used in calculation antipsychotic <- c("olanzapine", "olanzapine", "quetiapine", "ziprasidone") dose <- c(10, 12.5, 300, 60) example_oral <- data.frame(participant_ID, age, antipsychotic, dose, stringsAsFactors = FALSE) to_cpz(example_oral, ap_label = "antipsychotic", dose_label = "dose", route = "oral")
This package is not for clinical use. The authors assume no liability. All work must be verified independently. Use at own risk.
If you use this package in your scientific paper, please cite this package and the original papers from which the conversion factors are derived. The references can be viewed by using the built-in help function, e.g.
help(gardner2010), and as listed below. In addition, a spreadsheet-based tool facilitating dose equivalence conversion has been published by Leucht et al. (2020).
Davis, J. (1974). Dose equivalence of the anti-psychotic drugs. Journal of Psychiatric Research, 11, 65-69. <https://doi.org/10.1016/0022-3956(74)90071-5> Gardner, D. M., Murphy, A. L., O’Donnell, H., Centorrino, F., & Baldessarini, R. J. (2010). International consensus study of antipsychotic dosing. The American Journal of Psychiatry, 167(6), 686–693. <https://doi.org/10.1176/appi.ajp.2009.09060802> Leucht, S., Samara, M., Heres, S., & Davis, J. M. (2016). Dose Equivalents for Antipsychotic Drugs: The DDD Method. Schizophrenia Bulletin, 42(suppl_1), S90–S94. <https://doi.org/10.1093/schbul/sbv167> Leucht, S., Crippa, A., Siafis, S., Patel, M., Orsini, N. & Davis, J. M. (2020). Dose-Response Meta-Analysis of Antipsychotic Drugs for Acute Schizophrenia. American Journal of Psychiatry. 117(4). <https://doi.org/10.1176/appi.ajp.2019.19010034> Woods, S. (2003). Chlorpromazine Equivalent Doses for the Newer Atypical Antipsychotics. Journal of Clinical Psychiatry. 64(6). 663-667. <https://doi.org/10.4088/JCP.v64n0607>