TMP-SMX calculator

Trimethoprim-sulfamethoxazole (TMP-SMX AKA co-trimoxazole; brand name: Bactrim) is one of my favorite antibiotics to prescribe, but my least favorite to dose! It is dosed based off of the trimethoprim (TMP) component, and comes in "single strength" (80 mg of TMP) and "double strength" (160 mg) formulations.

To use this tool, you will want to input some information about the patient ( weight, height, sex), and the targeted daily dose of the trimethoprim component. When given these inputs, it will calculate the daily amount of TMP (mg/day) and estimate the number of single strength tablets that would be needed.

You can also design an optional dosing schedule using the buttons under the dosing input section

TODO list:

Mobile formatting
Warnings for extreme values in inputs
Warnings for high TDD of bactrim

MIT License & terms

Copyright (c) 2025 Hunter Ratliff

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Reliance on any information provided herein is solely at your own risk. The creator of this tool are not responsible for the accuracy or completeness of the information.

TMP-SMX calculator