The proposed mechanisms for the impairment of drug metabolism in CKD include alterations in gene transcription and protein translation, reduced CYP expression due to inhibition of hemoprotein biosynthesis and/or increased enzyme degradation, depletion of cofactors (e.g., supply of nicotinamide adenine dinucleotide phosphate (NADPH)), and direct competitive inhibition of CYP enzyme by circulating uremic constituents (Nolin et al., 2008). The gene discussed is PPIG; the disease is chronic kidney disease.