Pathways of Biotransformation — Phase I Reactions

Anesthesia in the Postgenomic Era: Commercial Polymorphism Screening in a Cardiac Surgery Patient

“…These modifications may also be referred to as "phase 1 reactions." 3 Many physicians, however, are most familiar with the role CYP450 proteins can play in pharmacokinetics as direct metabolizers of drugs, conversion of inactive administered compounds to active forms, or as mediators of drug-drug interactions by way of CYP450 induction or suppression. 2 The clinical relevance of CYP450 polymorphisms can be seen in the example of metoprolol metabolism in individuals with variances in CYP2D6 activity.…”

“…2 These enzymes perform oxidative, peroxidative, and reductive changes on a variety of endogenous compounds, including steroids, sterols, eicosanoids, uroporphyrinogens, bile acids, vitamin D, retinoids, and saturated and unsaturated fatty acids. These modifications may also be referred to as “phase 1 reactions.” 3 Many physicians, however, are most familiar with the role CYP450 proteins can play in pharmacokinetics as direct metabolizers of drugs, conversion of inactive administered compounds to active forms, or as mediators of drug-drug interactions by way of CYP450 induction or suppression. 2…”