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
A 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 2 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 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.

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.

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 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: 2/5/2021

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at healthlibrarysupport@ebsco.com. Our Health Library Support team will respond to your email request within 2 business days.