A method for screening a drug for cytochrome P450 (CYP) induction is provided and can include incubating the drug with a microsome-containing biological sample and then quantitating at least one cytochrome P450 isoform. The isoforms can be selected from 2B6, 3A4, 1A2, and 3A5 isoforms. In some embodiments, the method uses liquid chromatography tandem mass spectrometry (LC-MSMS). A quantitated value can be compared to a threshold value and the drug can be determined to exhibit an acceptable CYP induction potential when the quantitated value does not exceed the threshold value. Isolated peptides are also provided.