Objective: To determine whether long-term phentermine treatment produces any sign or symptom of abuse or addiction.
Date of Research Idea: October 2007.
Collaborators: Frank L. Greenway, M.D., Pennington Biomedical Research Center, Louisiana State University. Manit Srisurapanont, M.D., Ph.D., Chaig Mai University, Chang Mai, Thailand, Stacy Schmidt, University of Colorado Anschutz Medical Center, Denver.
Description: A clinical trial using modern addiction medicine measurements to look for signs or symptoms of phentermine drug abuse, addiction or withdrawal in patients treated with phentermine for obesity short-term and long-term. All subjects were from my practice.
Funding: American Society of Bariatric Physicians.
· Phentermine pharmacotherapy for obesity for up to 21.5 years and at doses up to 112.5 milligrams per day does not induce abuse, or addiction.
· Phentermine pharmacotherapy does not induce phentermine drug cravings, a hallmark symptom of addiction.
· Abrupt treatment cessation of long-term phentermine treatment does not induce amphetamine-like withdrawal.
· The absence of phentermine abuse, phentermine addiction, cravings for phentermine, and any semblance of a withdrawal syndrome the concept that phentermine is an addicting substance is untenable.
· Hendricks EJ, Greenway F, Srisurapanont M, DeMarco D, Hendricks MJ. Long-term Phentermine Does Not Induce Amphetamine-like Dependence. 62nd Annual Obesity and Related Diseases Symposium of the American Society of Bariatric Physicians. Orlando: ASBP, 2012.
· Hendricks EJ, Greenway F, Srisurapanont M, Hendricks MJ, De Marco D. Long-term Phentermine Pharmacotherapy: An Investigation for Symptoms of Amphetamine-like Phentermine Dependence, Cravings, or Withdrawal. 62nd Annual Obesity and Related Disorders Symposium of the American Society of Bariatric Physicians. Orlando: ASBP, 2012.
· Hendricks EJ, Greenway F, Srisurapanont M, Schmidt S, et al. Long-term Phentermine Pharmacotherapy: An Investigation for Amphetamine-like Phentermine Addiction, Abuse, Cravings, or Withdrawal. European Congress on Obesity 2013. Liverpool, UK.
· Hendricks EJ, Greenway F, Srisurapanont M, Schmidt SM, De Marco D, Hendricks MJ et al. Long-term Phentermine Pharmacotherapy: An Investigation for Amphetamine-like Withdrawal. European Congress on Obesity 2013. Liverpool, UK.
Publication: Hendricks EJ, Greenway F, Srisurapanont M, Schmidt S, Haggard M, Souter S et al. Addiction Potential of Phentermine prescribed during Long-term treatment of Obesity. International Journal of Obesity 2013; In Press (Manuscript # 2013IJO00126).
Elapsed time: ~ 3 years, 9 months.
Significance: Phentermine is an effective anti-obesity medicine. Fears of causing addiction with long-term phentermine are exaggerated and are based on presumptions this study proves baseless. These fears present a needless barrier to better care for overweight and obese patients worldwide.