What Is the Best Prescription Weight Loss Pill?

Medically Reviewed on 6/2/2021

Many weight loss pills are available in the market. The best prescription pill for you depends on your weight loss goals, your tolerability to the pill prescribed and your coexisting health conditions, if any.
Many weight loss pills are available in the market. The best prescription pill for you depends on your weight loss goals, your tolerability to the pill prescribed and your coexisting health conditions, if any.

Are you one of those who cannot shed extra pounds despite diet and exercise? Is your weight causing back pain and joint aches or worse? In these cases, your doctor may recommend a prescription weight loss drug in addition to (and not instead of) proper exercise and a balanced diet.

Many weight loss pills are available in the market. These are U.S. Food and Drug Administration (FDA)-approved for use more than 12 weeks. The best prescription pill for you depends on your weight loss goals, your tolerability to the pill prescribed and your coexisting health conditions, if any.

The most common weight loss medications tend to be appetite suppressants. Others interfere with the body’s fat absorption. What works for you might not work as well for others. Weight loss drugs can work by following methods.

  • Decrease food intake (appetite suppressants)
  • Increase feeling of fullness
  • Both the above
  • Alter the metabolism of food

Four weight loss drugs have been approved by the FDA for long-term use.

These may be used as a single agent or in combination with another medicine to reduce the adverse events or abuse potential. Belviq (lorcaserin) is another weight loss drug. As of February 2021, the FDA has requested the manufacturer to voluntarily withdraw the drug from the US market because of evidence reporting an increased cancer risk in the clinical trial.

How do these pills work?

Drugs that reduce food intake:

  • Doctors usually prescribe the most common sympathomimetic drug called phentermine resin (phenyl-tertiary-butylamine), sold under the brand name Lonamin among others. Lonamin is the medication used together with diet and exercise to treat obesity.
  • Sympathomimetic agents suppress appetite and induce satiety (feeling of fullness).
  • These agents work by mimicking a neurotransmitter in the brain related to appetite called noradrenaline (NA).
  • They also increase NA activity in the hypothalamus (the feeding center of the brain).
  • NA binding and activity in the hypothalamus have a negative effect on appetite.

Common side effects include a fast heartbeat, high blood pressure, trouble sleeping, dizziness and restlessness.


  • Qsymia is a combination of two medications, namely, phentermine and topiramate. Phentermine reduces appetite and topiramate is used to treat seizures and migraines.
  • Qsymia is prescribed to help adults who are overweight or obese with weight-related medical problems lose weight and keep it off.
  • Qsymia helps curb hunger and makes people feel full sooner, allowing them to eat less.
  • Because Qsymia may lead to birth defects, women who are pregnant or planning to become pregnant should not take Qsymia. Women should avoid Qsymia if they are breastfeeding or if they have glaucoma or hyperthyroidism.

Drugs that alter the metabolism of food


  • It is a drug designed to treat obesity. It is marketed as a prescription drug under the trade name Xenical.
  • It prevents approximately 30 percent of dietary fat from meals being absorbed into the body.
  • Along with decreasing the absorption of dietary triglycerides, orlistat has been found to

Gastrointestinal adverse effects of orlistat act similar to negative reinforcement, encouraging those on the medication to adhere to a low-fat diet.

Drugs that increase fullness or satiety


  • It is a combination of two generic drugs, namely, bupropion and naltrexone. Bupropion is an antidepressant and naltrexone is used for drug addiction.
  • Contrave acts on the brain to reduce appetite and the desire to comfort eat.
  • People on the medication start by taking one tablet each morning and gradually work their way up to taking two tablets twice a day. The slow increase in dosage allows the body to adjust to the medication.
  • Contrave leads to greater weight loss than diet or exercise alone. According to a study, people taking Contrave lost 5.4 percent of their body weight on average.
  • However, common side effects may be seen. Hence, people should take it under their doctor’s supervision.
  • People should not take Contrave if they have a seizure disorder, uncontrolled high blood pressure or narcotic addiction (or if they are on medication to treat such an addiction).


  • Saxenda, a brand name for the medication liraglutide, is a prescription weight loss injection that’s self-administered once daily. When combined with a low-calorie diet and increased physical activity, it can help adults with obesity as well as those who have a body mass index (BMI) of 27 or higher and a weight-related medical condition to lose weight and keep it off.
  • Saxenda mimics the satiety hormone, helping control appetite and reduce eating.
  • Apart from common side effects such as nausea, Saxenda’s more serious but less common side effects include thyroid tumors (including cancer), gallbladder problems (including gallstones), kidney failure and inflammation of the pancreas.

The best treatment for a patient depends on their weight, health, risk factors and lifestyle. Some people find it difficult to adhere to the necessary lifestyle and dietary changes whereas others simply may not respond to the medication. Everyone using weight loss medication must be assessed by their doctor within six weeks to three months of starting the treatment to determine whether it is working effectively.

Health Solutions From Our Sponsors

Medically Reviewed on 6/2/2021
Medscape Medical Reference

Duke Global Health Institute