Drug washout issues in studies of cerebral metabolism by positron emission tomography in psychiatric patients.
Many studies of brain glucose utilization by positron emission tomography attempt to describe the modifications of the brain activity during psychiatric diseases. A major difficulty in such studies is the necessity to assess patients free of pharmacological treatment, in order to relate the measured changes in glucose utilization to the pathopsychology, and not to a drug effect. In this paper are reviewed the arguments from the literature allowing to estimate the drug washout time for considering the patients as drug-free. The review is focussed on the known effects of the psychotrops on brain glucose utilization. This time is approximately six months for the neuroleptics given orally, one month for antidepressants, and five and a half half-lives for benzodiazepines. Alternative research strategies for avoiding a long drug washout are mentioned, and ethical limitations are considered.
Service Hospitalier Frédéric Joliot, CEA, Orsay, France.
J L
JL
Martinot
D014151:Anti-Anxiety Agents / Q000493:pharmacokinetics; D000928:Antidepressive Agents / Q000493:pharmacokinetics; D014150:Antipsychotic Agents / Q000493:pharmacokinetics; D001569:Benzodiazepines; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D004992:Ethics, Medical; D006801:Humans; D001523:Mental Disorders / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism*; D011619:Psychotropic Drugs / Q000493:pharmacokinetics*; D014055:Tomography, Emission-Computed
D014151:Anti-Anxiety Agents; D000928:Antidepressive Agents; D014150:Antipsychotic Agents; D011619:Psychotropic Drugs; D001569:Benzodiazepines