A simple direct colorimetric test using a tetrabromophenolphthalein reagent for detecting basic drugs in urine is described. The response of 62 commonly encountered drugs and metabolites to this test are described and 39 of these compounds were found to react. The sensitivity for many of the drugs is adequate for their detection following recommended therapeutic doses.
![Benzoic acid,2-[(3,5-dibromo-4-hydroxyphenyl)(3,5-dibromo-4-oxo-2,5-cyclohexadien-1-ylidene)methyl]-,ethyl ester Structure](https://image.chemsrc.com/caspic/451/1176-74-5.png)