Plasma concentration of galantamine - influence of dose and body mass index in Alzheimer’s disease.

Background/objectives: Patients with Alzheimer’s disease (AD) are at present treated with galantamine without actual knowledge of plasma concentration levels. The aim of this presentation is to analyse the relationship between galantamine plasma concentration, dose, demographics and body mass index (BMI). Methods: A total of 84 AD patients recruited at the Memory Clinic in Malmö, Sweden, treated with galantamine were included in this study. The patients were investigated at baseline, at 2 months and every 6 months for a period of three years. Blood samples were obtained at 180 of these investigations for the analysis of plasma galantamine concentration. Efficacy measures including cognitive tests (MMSE), functional ratings (IADL) and BMI were simultaneously evaluated. The dose as well as the time from drug intake to plasma extraction was investigated. Results: The mean galantamine plasma concentration demonstrated a strong positive linear association with dose (r=0.51, p<0.001). Moreover, patients with separate doses of galantamine (8, 16 and 24 mg daily) differed significantly in plasma concentration (p<0.001). No gender differences regarding dose were observed. There was no linear relationship between galantamine plasma concentration and BMI in the entire cohort. When investigating the impact of gender, a negative linear association (r=-0.45, p=0.001) between concentration and BMI was found in the male group but not in the female. Age did not influence the plasma concentration level. In a multivariate general linear model with concentration as the dependent variable, gender (p=0.010) and BMI (p=0.038) but not age (p=0.540) were predictive factors. Conclusion: Galantamine plasma concentration demonstrated a strong relationship with dose. The dose did not differ between genders, whereas the impact of body mass index on plasma concentration was important only among the males.