Clinical Pharmacokinetics of Morphine

Abstract

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.

Key Words:

• Morphine
• pharmacokinetics
• oral
• rectal
• sublingual
• buccal
• intravenous
• intramuscular
• absorption
• distribution
• metabolism
• excretion
• pediatrics
• neonates
• geriatrics
• drug interactions

Additional information

Notes on contributors

Steven E. Kern

Cherokee Layson-Wolf, PharmD, is Assistant Professor at the University of Maryland School of Pharmacy. At the time that this review was conducted, she was a Community Care Pharmacy Practice Resident at Virginia Commonwealth University.

Perry G. Fine, MD, is Professor of Anesthesiology, School of Medicine and Associate Medical Director, Pain Management Center at the University of Utah Health Sciences Center, Salt Lake City; and National Medical Director, VistaCare, based in Scottsdale, AZ. This commentary is based on an article in Dr. Fine's VistaCare Palliative Medicine Monitor.

Jonathan R. Gavrin, MD, is the Internet editor for the Journal. He is Associate Professor of Anesthesiology and Adjunct Associate Professor of Medicine at the University of Washington School of Medicine; Associate Member, Fred Hutchinson Cancer Research Center; and Associate Director for Clinical Anesthesia Services, Harborview Medical Center.

Perry G. Fine, MD, is Professor of Anesthesiology, School of Medicine and Associate Medical Director, Pain Management Center at the University of Utah Health Sciences Center, Salt Lake City; and National Medical Director, VistaCare, based in Scottsdale, AZ. This commentary is based on an article in Dr. Fine's VistaCare Palliative Medicine Monitor.

Philip J. Wiffen, is the Regional Pharmaceutical and Prescribing Adviser, Anglia & Oxford Region of the National Health Service Executive, a member of the Oxford Regional Pain Relief Unit and Coordinating Editor of the Cochrane Collaboration Pain Palliative and Supportive Care Collaborative Review Group.

Perry G. Fine, MD, is Professor of Anesthesiology, School of Medicine; Associate Medical Director, Pain Management Center at the University of Utah Health Sciences Center, Salt Lake City; and National Medical Director, VistaCare, based in Scottsdale, AZ. This commentary is based on an article in Dr. Fine's VistaCare Palliative Medicine Monitor.