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The Role of Drugs in Combating Obesity and How These Drugs Affect Your Health

Understanding the effects and risks of your medication

What pharmaceutical options are available to patients to treat obesity, how do these medications work, what dangers do they pose and should you be asking your doctor to prescribe them for you? A brief overview of the market followed by an in-depth look at each medication currently available to patients in the US.

The prevalence of obesity has doubled worldwide since 1980, but a range of new treatments is being introduced to help patients lose weight. For years, the FDA did not approve any new drugs for use in the fight against obesity. With drugs being withdrawn, rather than approved, the list of available medications for obesity was rapidly shrinking.

In 2012, for the first time in 13 years the FDA approved a new drug, Belviq. Interestingly, in February of this year, 2020, the drug was withdrawn over cancer concerns (see below). It was one of only eight FDA approved drugs and in Europe, only three drugs have achieved licensing.

The role of Pharma in the fight against obesity

Obesity is a hugely complex issue. There are strong genetic and epigenetic factors, in addition to the influence of gut hormones, gut microbes and viruses, and environmental factors (such as the promotion of sugar and refined carbohydrates). There is also evidence that psychological and mental health conditions are risk factors for obesity, and vice versa. 

Obesity cannot be simply cured with a pill, but requires a multi-faceted approach to treatment that can involve life-style changes, surgery, diet, counselling and a pharmacological element. 

There is no magic pill in the fight against obesity and the use of medications should always be accompanied by a healthy diet and — if your health allows it — an exercise regime.

According to an NIH article, on average, people who take prescription medications as part of a lifestyle program lose between 3 and 9 percent more of their starting body weight than people in a lifestyle program who do not take medication.

Before we list drugs that may assist you to combat obesity, you should be made aware of the fact that drugs often have the reverse effect on your weight, not intentionally, but as a side effect. Drugs that cause weight gain include corticosteroids, atypical antipsychotics, combined oral contraceptives and beta-blockers. Discuss with your doctor, the option of replacing these medications with alternatives, if possible.

FDA Approved Medications

The following drugs have been approved in the U.S. to combat obesity. Each drug is listed with its method of action (how it works) and any associated health warnings.There are no approved medications for children under the age of 12, and only one drug is approved for children aged 12 and over, namely orlistat (Xenical).


Pregnant women should never take weight-loss medications. Women who are planning to get pregnant also should avoid these medications, as some of them may harm a fetus.


Available in lower dosages without prescription(Alli). Itis considered safe for long term use, although weight loss is modest. It is the only product licensed for use by children aged 12 years an over.

Method Of Action: A pancreatic lipase inhibitor that causes around 30% of dietary fat to be excreted unabsorbed in the faeces. Orlistat works in your gut to reduce the amount of fat your body absorbs from the food you eat.

Side effects: Common, including oily stools, cramps and occasional faecal incontinence. Risk improvement includes a reduction in the cumulative incidence of diabetes over four years of 37.3% in obese normoglycaemic subjects, reducing LDL cholesterol by 5–10%, and lowering blood pressure and HbA1c.

Warnings: Rare cases of severe liver injury have been reported. Avoid taking with cyclosporine. Take a multivitamin pill daily to make sure you get enough of certain vitamins that your body may not absorb from the food you eat

Liraglutide (Saxenda)

Available only as an injection and at a lower dosage under the name Victoza

Method of Action: A glucagon-like peptide-1 (GLP-1) receptor agonist, which is given as a daily subcutaneous injection and has been used as a glucose-lowering agent in diabetes. 

The mechanism is not entirely understood, but appears to regulate appetite by inducing a feeling of fullness and reducing hunger pains. The EMA recommends it should only be offered to adults with a BMI of more than 30, or 27 if they have a weight-related condition such as type 2 diabetes. Patients should receive a daily 3mg dose, with treatment stopped if body weight has not been reduced by at least 5% after 12 weeks.

Side Effects: nausea, diarrhea, constipation, abdominal pain, headache, raised pulse.

Warnings:May increase the chance of developing pancreatitis. Has been found to cause a rare type of thyroid tumor in animals.

Lorcaserin (Belviq)

Withdrawn from the market in February of 2020. There is an increased risk of developing cancer if you use this medication. This exert below from the FDA website

The U.S. Food and Drug Administration (FDA) has requested that the manufacturer of Belviq, Belviq XR (lorcaserin) voluntarily withdraw the weight-loss drug from the U.S. market because a safety clinical trial shows an increased occurrence of cancer. The drug manufacturer, Eisai Inc,. has submitted a request to voluntarily withdraw the drug.

US Food and Dug Administration

Phentermine-topiramate (Qsymia)

Method of Action: An Adult medication that combines a mix of two medications: phentermine, which lessens your appetite, and topiramate, which is used to treat seizures or migraine headaches. May make you less hungry or feel full sooner.

Common Side Effects: constipation, dizziness, dry mouth, taste changes, especially with carbonated beverages, tingling of your hands and feet and trouble sleeping.

Warnings: Don’t use if you have glaucoma or hyperthyroidism. Tell your doctor if you have had a heart attack or stroke, abnormal heart rhythm, kidney disease, or mood problems. MAY LEAD TO BIRTH DEFECTS. DO NOT TAKE QSYMIA IF YOU ARE PREGNANT OR PLANNING A PREGNANCY. Do not take if you are breastfeeding.

Naltrexone-bupropion (Contrave)

Method of Action: An adult medication utilizing a mix of two medications: naltrexone, which is used to treat alcohol and drug dependence, and bupropion, which is used to treat depression or help people quit smoking. May make you feel less hungry or full sooner.

Common Side Effects: constipation, diarrhea, dizziness, dry mouth, headache, increased blood pressure, increased heart rate, insomnia, liver damage, nausea and vomiting.

Warnings: Do not use if you have uncontrolled high blood pressure, seizures or a history of anorexia or bulimia nervosa . Do not use if you are dependent on opioid pain medications or withdrawing from drugs or alcohol. Do not use if you are taking bupropion (Wellbutrin, Zyban). MAY INCREASE SUICIDAL THOUGHTS OR ACTIONS.

There are other medications that curb your desire to eat and these include;

  • phentermine
  • benzphetamine
  • diethylpropion
  • phendimetrazine

Method of Action: Increase chemicals in your brain to make you feel you are not hungry or that you are full.These drugs are FDA-approved only for short-term use — up to 12 weeks

The following applies to all four the drugs listed above.

Common Side Effects: dry mouth, constipation, difficulty sleeping, dizziness, feeling nervous, feeling restless, headache, raised blood pressure, raised pulse

Warnings: Do not use if you have heart disease, uncontrolled high blood pressure, hyperthyroidism, or glaucoma. Tell your doctor if you have severe anxiety or other mental health problems.

Off-Label Use of Prescription Drugs by Doctors

Sometimes doctors use medications in a way that’s different from what the FDA has approved, known as “off-label” use. By choosing an off-label medication to treat overweight and obesity, your doctor may prescribe

  • a drug approved for treating a different medical problem
  • two or more drugs at the same time
  • a drug for a longer period of time than approved by the FDA

You should feel comfortable asking your doctor if he or she is prescribing a medication that is not approved just for treating overweight and obesity. Before using a medication, learn all you need to know about it.

There are excellent and reliable government resources available online. Simply type in the name of the medication into Google and look for links to the NIH or FDA. Pharmaceutical websites such as also offer detailed breakdowns of the drugs they sell.

Lastly, remember that a medication is only effective when used as part of a larger treatment plan that includes steps to address your diet, lifestyle and other factors. If you suffer from depression because of obesity be particularly careful of the medication listed above and always make your doctor aware of how you are feeling.

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Medika Life provided this material for your information. It is not intended to substitute for the medical expertise and advice of your health care provider(s). We encourage you to discuss any decisions about treatment or care with your health care provider. The mention of any product, service, or therapy is not an endorsement by Medika Life

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