Determining the Effect of Abiraterone on the Metabolism of Oxycodone in Men With Prostate Cancer (the ENABLE Study)

Inclusion Criteria: * Diagnosed prostate cancer; * Males aged 18 years or older; * Treated with abiraterone 1000 mg once daily for at least 10 days (abiraterone arm). * Not treated with abiraterone 1000 mg once daily for at least 10 days (control arm). Exclusion Criteria: * Use of oxycodone short acting \<48 hours, or long acting \<96 hours prior to the study day; * Use of other opioids in the 14 days prior to the study day (see also appendix A); * Use of other medication that has pharmacokinetic or pharmacodynamics interactions with oxycodone (see also appendix A); * Arm 1: dose reduction or successive days of treatment interruption within 10 days prior to the study day (arm 1); * Arm 2: treatment with abiraterone within 10 days prior to the study day; * A body mass index (BMI) outside the range of 18 - 30 kg/m2; * If hypersensitive to oxycodone; * patients suffering from diarrhea * If any type of abnormality; active or symptomatic viral hepatitis or chronic liver disease (e.g. classification with Child-Pugh B, Child-Pugh C); * Known metastases in the liver that would affect drug metabolism; * Patients with a CYP3A4 or CYP2D6 polymorphism; * Moderate-severe renal dysfunction (GFR \<60 ml/min/1.73m2) that affects drug metabolism ; * Subjects with significant respiratory depression resulting in the need of oxygen therapy or objective hypoventilation (respiratory rate \<12/min); * Hypercapnia (venous pCO2 outside the range of 5.5 - 6.7; pH outside the range 7.30 - 7.40); * Subjects with, a history of bronchial asthma, chronic obstructive pulmonary disease or pulmonary heart disease; * Subjects who started their first cycle of chemotherapy during the 2 weeks before the study day; * Major surgery within 1 month prior to screening or planned surgery; * A history of drug abuse * Patients receiving opioid substitution therapy for opioid addiction (e.g. methadone or buprenorphine) and/or suffering from opioid withdrawal * Patients with evidence of clinically significant gastrointestinal disease; * Patients who are contraindicated for blood sampling; * Unable to swallow solid, oral dosage forms whole with water; * Participation in a clinical trial study at the time of enrolment or within 30 days or 5 half-lives of enrolment, whichever is longer; * Previous gastric bypass or gastric band surgery.