Clinical Research Directory

Inclusion Criteria: * Adults aged 18 years or older * Receiving opioid therapy (tramadol, tapentadol, morphine, fentanyl, or buprenorphine) as part of routine clinical care * Stable opioid treatment for at least a predefined minimum period prior to enrollment (according to the study protocol) * Ability to provide written informed consent * Ability to comply with study procedures, including blood sampling and completion of questionnaires Exclusion Criteria: * Acute opioid intoxication or withdrawal at the time of enrollment * Use of investigational drugs or participation in another interventional clinical trial that could interfere with study outcomes * Severe acute illness or unstable medical condition that, in the investigator's judgment, would interfere with study participation * Known pregnancy or breastfeeding * Inability to provide informed consent * Any condition that, in the opinion of the investigator, would make participation unsafe or compromise the quality of the collected data