by EBSCO Medical Review Board

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

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

Prescription Medicines

Central Nervous System Medications

  • Phentermine
  • Phendimetrazine
  • Diethylpropion
  • Phentermine plus topiramate

Fat Absorption Blockers

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

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

  • Liraglutide
  • Semaglutide

Monoamine Oxidase Inhibitors (MAOI)

  • Naltrexone-Bupropion

Prescription Medicines

Central Nervous System Medicines

For adults:

  • 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. 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:

  • Phentermine and amphetamine sulfate:
    • Problems passing urine (peeing)
    • 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. 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 (poop)
  • Pooping more often
  • Liver damage (rare)
Glucagon-Like Peptide-1 (GLP-1) Inhibitors
  • Liraglutide
  • Semaglutide

This medicine is used for long term weight control. It is for people with one or more weight-related problems. 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 long term 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

Obesity. Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/nutritional-disorders/obesity-and-the-metabolic-syndrome/obesity. Accessed May 5, 2022.

Weight loss medications for obesity in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/management/weight-loss-medications-for-obesity-in-adults-16. Accessed May 5, 2022.

Weight loss medications for obesity in children and adolescents. EBSCO DynaMed website. Available at: https://www.dynamed.com/management/weight-loss-medications-for-obesity-in-children-and-adolescents. Accessed May 5, 2022.

Wilding JP. Combination therapy for obesity. J Psychopharmacol. 2017;31(11):1503-1508.

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