title: Cannabinoid-opioid interaction in chronic pain.
abstract: Cannabinoids and opioids share several pharmacologic properties and may act synergistically. The potential pharmacokinetics and the safety of the combination in humans are unknown. We therefore undertook a study to answer these questions. Twenty-one individuals with chronic pain, on a regimen of twice-daily doses of sustained-release morphine or oxycodone were enrolled in the study and admitted for a 5-day inpatient stay. Participants were asked to inhale vaporized cannabis in the evening of day 1, three times a day on days 2-4, and in the morning of day 5. Blood sampling was performed at 12-h intervals on days 1 and 5. The extent of chronic pain was also assessed daily. Pharmacokinetic investigations revealed no significant change in the area under the plasma concentration-time curves for either morphine or oxycodone after exposure to cannabis. Pain was significantly decreased (average 27%, 95% confidence interval (CI) 9, 46) after the addition of vaporized cannabis. We therefore concluded that vaporized cannabis augments the analgesic effects of opioids without significantly altering plasma opioid levels. The combination may allow for opioid treatment at lower doses with fewer side effects.
authors: Division of Hematology-Oncology, San Francisco General Hospital, University of California, San Francisco, San Francisco, California, USA. dabrams@hemeonc.ucsf.edu
authors: D I
authors: DI
authors: Abrams
authors: P
authors: P
authors: Couey
authors: S B
authors: SB
authors: Shade
authors: M E
authors: ME
authors: Kelly
authors: N L
authors: NL
authors: Benowitz
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D019540:Area Under Curve; D059350:Chronic Pain / Q000188:drug therapy*; D003692:Delayed-Action Preparations; D013759:Dronabinol / Q000009:adverse effects / Q000494:pharmacology*; D004334:Drug Administration Schedule; D004357:Drug Synergism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010098:Oxycodone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D009020:Morphine; D013759:Dronabinol; D010098:Oxycodone