Monitoring Anti-Dementia Drugs by Serum Levels

Overview

The main objective of the MONANTI study is twofold: Firstly, to determine the serum concentration (SC) the anti-dementia drugs donepezil and memantine in a broadly defined clinical population of patients suffering from dementia treated with the two drugs in question. Secondly, to determine whether adjustment of treatment of anti-dementia medication based on measurements of the SC will benefit patients in terms of cognitive performance, activities of daily living (ADL), frequency and severity of side effects. The reason for conduction of this study is that the relationship between serum-level of anti-dementia drugs, clinical efficacy, compliance and side effects has only been scarcely investigated. Both a previously published study and a preliminary (pilot)study conducted imply that roughly 50 % of patients on donepezil have SC outside the recommended therapeutic reference range (TRR). Thus, MONANTI will investigate if this is indeed the case in a broadly comprised population of patients with dementia treated with donepezil or memantine. In addition, MONANTI will link SC to co-morbidity, level of compliance, medication interactions. It is hypothesized that the efficacy of anti-dementia drugs can be significantly improved by adjustment of treatment according to SC. Also, it is hypothesized that the burden of side effects can be reduced in patients in whom too high SC are detected, if dose reduction or change of treatment drug is done. MONANTI is a randomized study, in which the assessor is blinded to avoid related biases to the extent possible. To meet the enrollment criteria eligible participants must: A) be newly diagnosed with either Alzheimer's disease dementia, dementia with Lewy-bodies or Parkinson's disease with dementia and B) be scheduled for treatment with either donepezil or memantine. C) not meet a list of (exclusion) criteria, which have been set up in order to avoid blur and biases of the results. D) be able to give written informed consent to participation in presence of a close relative. After enrollment the participants will be randomly assigned to one of two study groups. In the first of these, the control group, the participants receive standard treatment and follow-up at the outpatient clinic. In addition, all participants in the control group who complete the trial will have a blood sample collected at the final visit to measure the SC of the anti-dementia drug along with a genetic test for a few key genes thought to be relevant for the study (two liver enzymes (cyp2D6, cyp3A4/5, APOE-genotype, butyrylcholine-esterase K-variant). In the other group, the intervention group, the participators will be closely monitored for side effects after prescription of anti-dementia drugs. All participants in the intervention group will be offered a measurement of the SC in case they experience drug side effects within 2 months of treatment initiation. All participants in the intervention group will have a measurement of the SC done at the 6 months visit. The measured SC will be compared to the TRR of the drug in question. This information, along with details from the clinical assessment at the 6 month visit will be used to guide the decision of whether or not to adjust treatment. All decisions on treatment adjustment during the trial are done by the PI according to details in the protocol. All participants in the intervention group are evaluated again at a 12 month visit, identical to that of the control groups. To assess the possible effects of SC guided treatment adjustment six clinical tests/rating scales will be used (MMSE, ACE, NPI-Q, DAD, CGI, GDS). The tests/rating scales will be administered both at the enrollement visit and one year later at the final 12 month follow-up visit. To measure the effect of donepezil on brain cholinergic function approx. 30 participants will be recruited for electroencephalography (EEG). These participants will have an EEG done at enrollment and after 12 months. In addition to the above mentioned quantitative study a qualitative study with relatives of enrolled participants is planned. All the needed approvals have been obtained according to Danish law (approval by the Danish Data Protection Agency, Scientific Ethics Committee for Region Sjaelland, The Danish Medical Agencies).