Impact of CYP2D6 and CYP3A4 genetic polymorphism on combined cholinesterase inhibitors and memantine treatment in mild to moderate Alzheimer's disease.

AIM: The impact of CYP2D6 and CYP3A4 polymorphism on the steady-state plasma concentrations and therapeutic outcome of donepezil monotherapy and combination therapy in Alzheimer's disease (AD) patients.
METHODS: A total of 38 patients for donepezil and 17 patients for donepezil and memantine therapy, aged ≥ 55 years, were recruited meeting inclusion and exclusion criteria. Polymerase chain reaction-restriction fragment length polymorphism was performed. The liquid chromatography-tandem mass spectrometry method was used for estimation of drug levels of donepezil and memantine.
RESULTS: Significant allele frequency was observed for CYP2D6*3 polymorphism in patients on donepezil monotherapy and combination therapy. Significant allele frequency for CYP2D6*4 was observed in the patients on donepezil monotherapy.
CONCLUSION: CYP2D6 polymorphism, though not significant, might partially be involved in the plasma concentration of AD drug.