Here are the basics about each of the medicines below. Only common problems with them are listed.

These medicines should only be used with diet changes, exercise, and therapy.

Prescription Medicines

Central Nervous System Medications

  • Lorcaserin
  • Phentermine
  • Phendimetrazine
  • Diethylpropion
  • Phentermine plus topiramate

Fat Absorption Blockers

  • Orlistat (as prescription or over-the-counter)

Glucagon-Like Peptide-1 (GLP-1) Inhibitors

  • Liraglutide

Monoamine Oxidase Inhibitors (MAOI)

  • Naltrexone-Bupropion

Prescription Medicines

 

Central Nervous System Medicines

For adults:

  • Lorcaserin
  • Phentermine
  • Phendimetrazine
  • Diethylpropion
  • Phentermine plus topiramate

For children and young adults:

  • Amphetamine sulfate (for children over 11 years old)
  • Phentermine or diethylpropion (for children over 16 years old)

These medicines act on the brain to lower appetite. Lorcaserin is for long-term use. Phentermine, phendimetrazine, and diethylpropion should only be used up to a few weeks.

Some problems are:

  • Lightheadedness
  • Dry mouth
  • Headache
  • Constipation or diarrhea
  • Nausea
  • Nervousness
  • Sleeplessness
  • Restlessness
  • High blood pressure
  • Heart problems

Also:

  • Lorcaserin
    • Fatigue
    • Back pain
    • Cough
  • Phentermine and amphetamine sulfate:
    • Problems passing urine
    • Rash
  • Phentermine plus topiramate
    • Numbness or tingling of skin
    • Change in taste
    • Depression
 

Fat Absorption Blockers

Orlistat:

  • Xenical (prescription)
  • Alli (over-the-counter)

This medicine can be used by adults and children over 11 years old. Xenical stops the fat a person eats from being absorbed by blocking digestive enzymes. About 30% of fat will stay in the bowels. In some people, the fat leaves the body between bowel movements as an oily discharge. It can be used long-term (up to about 2 years). Orlistat also has an over-the-counter form called Alli.

Some problems may be:

  • Staining of underwear
  • Gas
  • Pressure to empty bowels
  • Leakage of stool
  • Moving the bowels more often
  • Liver damage (rare)
 

Glucagon-Like Peptide-1 (GLP-1) Inhibitors

  • Liraglutide

This medicine is used for chronic weight control in people who have at least one other weight-related problem. It works by making a person feel less hungry or fuller faster while eating. It is given as a daily shot. The dose is slowly raised to 3 mg a day.

Some problems may be:

  • Nausea
  • Constipation
  • Diarrhea
  • Belly pain
  • Headache
  • Fast heart rate
  • An higher risk of pancreatitis
 

Monoamine Oxidase Inhibitors (MAOI)

  • Naltrexone-Bupropion

This medicine is used for chronic weight control. It combines two drugs. It works by making a person feel less hungry or fuller faster while eating. The dosage is slowly raised from one to two tablets a day.

It should not be taken by people with poorly controlled high blood pressure, seizures, eating disorders ( anorexia or bulimia), opioid dependency, or alcohol and drug withdrawal. People who already take bupropion should not take this medicine.

Some problems are:

  • Lightheadedness
  • Constipation
  • Diarrhea
  • Nausea or vomiting
  • Dry mouth
  • Sleeplessness
  • Fast heart rate
  • High blood pressure
  • Liver damage

NOTE: This medicine may cause suicidal thoughts or actions.

Over-the-Counter (OTC) Medicines

Alli is the only OTC weight loss medicine that is helpful. Others have led to severe health problems. They should not be taken without talking to a doctor first.

REFERENCES:

Meridia (sibutramine): market withdrawal due to risk of serious cardiovascular events. US Food & Drug Administration website. Available at: https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm228830.htm. Updated September 9, 2013. Accessed February 23, 2017.

Meridia (sibutramine hydrochloride): follow-up to an early communication about an ongoing safety review. US Food & Drug Administration website. Available at: https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm198221.htm. Updated September 9, 2013. Accessed February 23, 2017.

Obesity. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/nutritional-disorders/obesity-and-the-metabolic-syndrome/obesity. Update December 2016. Accessed February 23, 2017.

Orlistat (marketed as Alli and Xenical): labeling change. US Food & Drug Administration website. Available at: https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm213448.htm. Updated September 6, 2013. Accessed February 23, 2017.

Pai You Guo, marketed as dietary supplement—recall. US Food & Drug Administration website. Available at: https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm190531.htm. Updated August 29, 2013. Accessed February 23, 2017.

Prescription medications for the treatment of obesity. National Institute of Diabetes and Digestive and Kidney Diseases. Available at: https://www.niddk.nih.gov/health-information/health-topics/weight-control/prescription-medications-treat-overweight-obesity/pages/facts.aspx. Updated July 2016. Accessed August February 23, 2017.

Weight loss medications for obesity in adults. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T361156/Weight-loss-medications-for-obesity-in-adults. Updated May 27, 2016. Accessed February 23, 2017.

Weight loss medications for obesity in children and adolescents. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T474269/Weight-loss-medications-for-obesity-in-children-and-adolescents. Updated January 27, 2016. Accessed February 23, 2017.

9/17/2010 DynaMed Plus Systematic Literature Surveillancehttp://www.dynamed.com/topics/dmp~AN~T116362/Weight-loss-medications-withdrawn-from-market: James WP, Caterson ID, Coutinho W, et al. Effect of sibutramine on cardiovascular outcomes in overweight and obese subjects. N Engl J Med. 2010;363(10):905-917.

Last reviewed November 2019 by EBSCO Medical Review Board Daniel A. Ostrovsky, MD  Last Updated: 1/30/2020