The "Skinny" on Weight Loss Medications

Updated: Aug 24, 2021

Zoe Schilling, PharmD. Candidate 2022


The United States prevalence of obesity was 42.4% in 2017 – 2018. From 1999 –2000 through 2017 –2018, U.S. obesity prevalence increased from 30.5% to 42.4%. The estimated annual medical cost of obesity in the U.S. was $147 billion in 2008. Overweight & obese patients have increased risk of all-cause mortality.

Increased morbidity from high blood pressure, high cholesterol, diabetes, heart disease, gallbladder disease, sleep apnea, and certain types of cancer.

The pathophysiology of obesity is complicated and could be very complex. Obesity may involve genetic factors, lifestyle, nutritional, behavioral, socioeconomic factors, and more.

What can we control?

  • Lifestyle (diet and exercise)

  • Medications

  • Stress

  • Smoking

Medications known to promote weight gain:

  • Insulin, glipizide, glyburide, glimepiride, pioglitazone, rosiglitazone (diabetes medications)

  • Olanzapine, clozapine, risperidone, aripiprazole (mood medications)

  • Gabapentin, pregabalin, valproic acid, and vigabatrin (anti-seizure medications)

  • Prednisone and other steroids

  • Amitriptyline, mirtazapine, paroxetine, escitalopram, sertraline, duloxetine, and citalopram (mood medications)

  • Note: this is not a comprehensive list; there may be other indications for these medications. Talk to your doctor or pharmacist if you think one of your medications may be causing weight gain

Highlights of Obesity Management Guidelines:

Nutritional, exercise & behavioral modifications are always preferred over pharmacotherapy

• Pharmacotherapy only plays a supportive role. Most patients most meet a BMI requirement to initiate drug therapy

• Emphasis should be on the patient as a whole while creating sustainable lifestyle changes

• Identification of food triggers, emotional eating, stress management

• Obesity management should focus on improved well-being, not just weight loss

• General exercise goal is for aerobic activity (30– 60 min) on most days of the week

• Weight loss achieved with lifestyle changes is about 3%–5% of body weight, which can result in meaningful improvement in obesity-related comorbidities

• Sustainable, caloric restriction is a major key to successful weight loss

• Patients generally should drink more water

• Always include protein & veggies at every meal

• Stress the importance of adequate sleep

• Encourage patients not to skip meals, especially breakfast

Patients should be encouraged to consume more:

Whole grains (whole wheat, steel cut oats, brown rice, quinoa)

Vegetables (a colorful variety-not potatoes)

Whole fruits (not fruit juices)

Nuts, seeds, beans, and other healthful sources of protein (fish and poultry)

Plant oils (olive and other vegetable oils)

• Use fiber supplements in patients when necessary

Patients should be encouraged to consume less:

• Sugar-sweetened beverages (soda, sports drinks)

• Alcoholic beverages

• Fruit juice (no more than a small amount per day)

• Refined grains (white bread, white rice, white pasta)

• Potatoes (baked or fried)

• Red meat (beef, pork, lamb) and processed meats (salami, ham, bacon, sausage)

Other highly processed foods, such as fast food

Common Medications:

Note: Always talk to your doctor and/ or pharmacist before considering drug therapy.

Remember most medications need a prescription and you have to meet a certain BMI criterion to qualify for drug therapy.

  • If lifestyle changes fail to produce a result in six months, FDA-approved pharmacotherapy is recommended as an adjunct in high-risk patients

  • This recommendation is limited to patients with a BMI ≥ 30, or ≥ 27 with obesity-related risk factors or diseases present

  • Drugs should only used as adjuncts; patients must be exercising, with dietary changes & behavioral modification

Only Medication that can be bought over-the-counter (OTC):

Orlistat (Alli):

– Available with a prescription in a dose of 120 mg and was recently approved for a 60 mg dose available over the counter

–Patients on orlistat should take a multivitamin supplement

– To reduce the risk for regaining weight after prior weight loss

– For obese patients with initial BMI ³30 kg/m2 or ³27 kg/m2 in the presence of other risk factors (ex. hypertension, diabetes, dyslipidemia)

– Contraindicated in patients with chronic malabsorption syndrome or cholestasis and in patients with known hypersensitivity to orlistat

Most commonly reported side effects include fecal urgency, flatulence, increased defecation, fatty/oily stool

Prescription Medications May Include:

Naltrexone/Bupropion (Contrave):

– Contraindicated with a history of seizure disorder, opioid treatment, pregnancy

Common side effects include: nausea, vomiting, diarrhea, insomnia, headache


– Used off-label for weight loss

–May decrease the impulses that binge eaters experience to help with weight loss