Effects and Cost-Effectiveness of Pharmacogenetic Screening Among Elderly Starters With Antidepressants: A Pragmatic Randomized Controlled Trial
Overview
- Phase
- Phase 4
- Intervention
- Not specified
- Conditions
- Depression
- Sponsor
- University of Groningen
- Enrollment
- 202
- Locations
- 11
- Primary Endpoint
- Serum drug levels of nortriptyline or venlafaxine
- Status
- Completed
- Last Updated
- 8 years ago
Overview
Brief Summary
Depression is common among elderly with an estimated prevalence of 5%. Due to ageing the national burden will double in the coming decade. Antidepressants as TCAs and SSRIs are effective in reducing symptoms, especially in people with severe depression. To optimize treatment efficacy and reduce side effects, the Pharmacogenetics Working Group of the Royal Dutch Pharmacists Association developed guidelines for dose-adaptation, for instance for antidepressants such as nortriptyline and venlafaxine based on their main relevant genotype (CYP2D6) accompanied by Therapeutic Drug Monitoring. Such personalized drug dosing based on pharmacogenetic information at the start of therapy can speed up the titration phase of antidepressants to establish an adequate maintenance dose. However, pharmacogenetic screening programs are expensive and evidence on effects and costs of such a program among elderly antidepressant starters from randomized controlled studies is lacking. The investigators will conduct a pragmatic randomized controlled trial to determine the effects and costs of pharmacogenetic screening information to optimize drug dosing in depressed elderly patients who start with nortriptyline or venlafaxine.
Objective: The primary objective is to determine the effects of pharmacogenetic screening for CYP2D6 on the time to reach adequate blood levels as an accepted proxy for adequate treatment. Secondary objectives include adverse drug reactions and cost-effectiveness
Study design: pragmatic randomized controlled intervention study
Detailed Description
This study is a multicenter randomized controlled trial in which psychiatric elderly care centers participate in the Netherlands. Deviating genotypes are expected to be found in \~30% of the population, therefore the study consist out of two parts. First a basic study in which \~750 patients, starting with nortriptyline or venlafaxine will be genotyped to identify patients with deviating genotypes (Poor, Intermediate or Ultrarapid Metabolizers). Second in the main study 150 patients with a deviating genotype are randomly allocated to two study arms one with and one without information on the genotype. From the extensive metabolizers('normal'genotype) 75 patients are allocated to a third arm as an external control.
Investigators
Prof. Dr. Bob Wilffert
Prof. Dr. Bob Wilffert
University of Groningen
Eligibility Criteria
Inclusion Criteria
- •Major depression according to DSM-IV (296.2x, 296.3x) criteria for which the treating psychiatrist decided to start drug treatment with either nortriptyline or venlafaxine.
- •Competent to understand the informed consent procedure
Exclusion Criteria
- •Use of clinically relevant CYP2D6 inhibitors
- •Use of clinically relevant CYP2D6 inducers
- •Use of other drugs that affect plasma levels as co-medication
- •Serious hepatic failure
- •Patients for which drug treatment with venlafaxine is started and a GFR \< 30 ml/min.
- •Patients with the very rare genotype: Intermediate Metabolizer with duplications (IMDUP).
Outcomes
Primary Outcomes
Serum drug levels of nortriptyline or venlafaxine
Time Frame: After 2, 4 and 6 weeks treatment started, after the 6th week sampling continues every 2 weeks untill adequate serum drug level is reached with an expected average of 8 weeks
Serum drug levels will be assessed by 'dried blood spot' analysis, blood will be obtained by a fingerprick. Adequate serum drug levels is defined as: serum drug levels within the therapeutic window (for nortriptyline 50-150 µg/L, for venlafaxine 200-400 µg/L in combination with stable drug dosing for at least 3 weeks.
Secondary Outcomes
- Quality of life questionnaire(After 2, 4 and 6 weeks treatment started and if adequate serum drug levels are not reached in 6 weeks, every 2 weeks, untill adequate serum drug levels are reached with an expected average of 8 weeks)
- Adverse drug events Questionnaire(At start of treatment and from that moment on, every 2 weeks untill adequate drug serum levels are reached with an expected average of 8 weeks)
- Self reported Severity of depression Questionnaire(After 2, 4 and 6 weeks treatment started and if adequate serum drug levels are not reached in 6 weeks, every 2 weeks, untill adequate serum drug levels are reached with an expected average of 8 weeks)
- Productivity Questionnaire(After 2, 4 and 6 weeks treatment started and if adequate serum drug levels are not reached in 6 weeks, every 2 weeks, untill adequate serum drug levels are reached with an expected average of 8 weeks)
- Drug use(At inclusion, after 2, 4 and 6 weeks after inclusion and if adequate serum drug levels are not reached in 6 weeks, every 2 weeks, untill adequate serum drug level is reached with an expected average of 8 weeks)
- Data on health care associated resource use(After 2, 4 and 6 weeks treatment started and if adequate serum drug levels are not reached in 6 weeks, every 2 weeks, untill adequate serum drug levels are reached with an expected average of 8 weeks)