PHASE II METABOLISM
Phase II reactions typically involve conjugation of a substrate with glucuronic acid. This makes the drug water-soluble and prepped for renal excretion.
The responsible enzyme is UDP-glucuronosyltransferase, abbreviated UGT, as in “U Got Tagged” with glucuronic acid.
Medications metabolized primarily by Phase II are relatively immune to drug interactions. Examples of clinically relevant Phase II interactions are those involving lamotrigine (Lamictal) as a substrate.