Associate Professor

Hance Clarke



University Health Network - Toronto General Hospital
200 Elizabeth Street, PMB-100L , Toronto, Ontario Canada M5G 2C4
Research Interests
acute pain, chronic pain, medical cannibis
Clinical Interests
acute pain, chronic pain
contact faculty member for more information

Dr. Clarke is the director of Pain Services and the medical director of the Pain Research Unit at the Toronto General Hospital. He is appointed to the Institute of Medical Sciences at the University of Toronto and is a graduate of the Royal College Clinician Scientist Program. His research interests include identifying novel acute pain treatments following major surgery, identifying the factors involved in the transition of acute postsurgical pain to chronic pain, studying the genetics of acute and chronic pain after surgery, and identifying risk factors associated with continued opioid use and poor health related quality of life after major surgery as well as the efficacy of hyperbaric medicine. Over the past five years he has authored 47 peer reviewed manuscripts. 


Research Synopsis


Dr. Clarke has contributed significantly to establish a rational, empirical approach to the “Great Opioid Debate,” an article in the British Medical Journal (Impact factor: 16.3) on prolonged opioid use after major surgery. The study is the largest of its kind, based on more than 39,000 patients who had undergone major elective surgery. The data show that ~3% of patients continue to use opioids 3 months after surgery. Dr. Clarke argues that pain - not ‘addiction’ - is likely the main culprit in the continued use of opioids. Regardless of one’s position in the current debate on the use and abuse of opioids for chronic pain, his research group brings a welcomed, rational, data-driven approach to the problem. 

Dr. Clarke has also published an invited review in the Canadian Journal of Anesthesia reviewing the current state of knowledge on the genetics of chronic post-surgical pain. The manuscript, published in March 2015, reviews what is known about the genetic variation in the many genes that increase the risk for developing chronic post-surgical pain. The paper discusses pharmacogenomic approaches to chronic post-surgical pain management as well as personalized, mechanism-based pain treatments.

Dr. Clarke's team has also developed a world-first Transitional Pain Service. The statistics are clear: moderate to severe chronic postsurgical pain occurs in upwards of 10% of patients after major surgery. This is a world-wide problem. They have assembled a multidisciplinary team of health care professionals with expertise in chronic pain mechanisms and management.  Under his leadership, The Transitional Pain Service, funded by the Ontario Ministry of Health and Long-term Care, aims to be proactive in optimizing pain control in at-risk patients who have undergone major surgery so that they do not go on to develop chronic postsurgical pain.  He has recently published a manuscript in the Journal of Pain Research which templates the Transitional Pain Research Program for others to emulate. 


Recent Publications


Joel Katz, Aliza Weinrib, Samantha R. Fashler, Rita Katznelzon, Bansi R. Shah, Salima Ladak, Jiao Jiang, Qing Li, Kayla McMillan, Daniel Santa Mina, Kirsten Wendtlandt, Karen McRae, Diana Tamir, Sheldon Lyn, Marc de Perrot, Vivek Rao, David Grant, Graham Roche-Nagle, Sean Cleary, Stefan O.P. Hofer, Ralph Gilbert, Duminda Wijeysundera, Paul Ritvo, Tahir Janmohamed, Gerald O’Leary, and Hance Clarke. The Toronto General Hospital Transitional Pain Service: Development and Implementation of a Multidisciplinary Program to Prevent Chronic Postsurgical Pain. Journal of Pain Research. In Press 2015

Hance Clarke, Gabrielle Pagé, Colin McCartney, Alexander Huang, Paul Stratford, Jeffrey Andrion, Deborah Kennedy, Imad T. Awad, Jeffrey Gollish, Joel Katz.  Pregabalin reduces postoperative opioid consumption and pain for 1 week post hospital discharge, but not function at 6 weeks or 3 months after total hip arthroplasty. British Journal of Anesthesia. In Press 2015

Howard Meng, John G. Hanlon, Rita Katznelson, Anand Ghanekar, Ian Mc Gilvray, Hance Clarke. Medical cannabis for opioid weaning in a patient with complex pain following liver transplantation: A Transitional Pain Service Case Report.  Canadian Journal of Anesthesia. In Press 2015

James Khan, Clarita Margarido, PJ Deveraux, Hance Clarke, Andrea McLellan, and Stephen Choi. Preoperative Celecoxib in noncardiac surgery: A systematic review and meta-analysis of randomized controlled trial. European Journal of Anesthesiology. In Press, 2015

Alexander Huang, Joel Katz and Hance Clarke. Ensuring safe prescribing of controlled substances for pain following surgery by developing a transitional pain service. Pain Management 2015 Mar;5(2):97-105

Hance Clarke, Michael Poon, Aliza Weinrib, Rita Katznelson, Kirsten Wentlandt, and Joel Katz. Preventive Analgesia and Novel Strategies for the Prevention of Chronic Post Surgical Pain. DRUGS 2015 Mar;75(4):339-51

Gabrielle Page, Joel Katz, Manolo Romero Escobar, Katy Curtis, Samantha Fuss, Noga Cohen & Hance Clarke. Not all Postoperative Pain is alike: A Pain Trajectory Analysis following Total Knee Arthroplasty. Pain 2015 Mar;156(3):460-8

Hance Clarke, Joel Katz, Herta Flor, Marcela Rietschel, Scott Diehl, & Ze’ev Seltzer. Genetics of Chronic Post-surgical Pain: A Crucial Step Toward Personal Pain Medicine. Canadian Journal of Anesthesia 2015 Mar;62(3):294-303

Lindsay C. Burns, Sarah E. Ritvo, Meaghan K. Fergusoon, Hance Clarke, Ze’ev Seltzer, and Joel Katz.  Pain Catastrophizing as a Risk Factor for Chronic Pain after Total Knee Arthroplasty: A Systematic Review. Journal of Pain Research 2015 Jan 5;8:21-32

Hance A. Clarke, Joel Katz, Colin McCartney, Paul Stratford, Deborah Kennedy, Gabrielle Page, Imad Awad, Jeffrey Gollish, & Joseph Kay.  Perioperative gabapentin reduces 24-hour opioid consumption and improves in-hospital rehabilitation but not post-discharge outcomes following total knee arthroplasty with peripheral nerve blockade. British Journal of Anesthesia. 2014 Nov;113(5):855-64 epub June 30, 2014



Director, Pain Services, Toronto General Hospital
Director, Transitional Pain Service
Medical Director, Pain Research Unit
Medical Director, Ehlers-Danlos Syndrome program


Honours and Awards

Name: Research Merit Awards


2015-2017 - Department of Anesthesia, University of Toronto
2013-2015 - Department of Anesthesia, University of Toronto
2011-2013 - Department of Anesthesia, University of Toronto

Name: STAGE Award

2013-2014 - Canadian Institutes of Health Research 

Name: Clinical Pain Management Fellowship Award

2012-2014 - Canadian Pain Society

Name: PhD Fellowship Award

2009-2012 - Canadian Institutes of Health Research



Course Number: DIRECTOR
Course Name: Acute Pain Residency Seminar Series
Course Number: NU 2102
Course Name: Clinical Pain
Course Number: ROP 299
Course Name: Undergraduate Research