NAPLEX Question of the Week: Weight Loss Medications

What medication is best to lose weight? Our case this week tackles this common conundrum.

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A 48 year old female comes to your ambulatory care clinic for a follow up appointment for weight loss. She has implemented strict lifestyle changes for the past 6 months but is still unable to lose weight. She is frustrated that she has not seen improvement with her efforts and asks if there is a medication she can take to help with her weight loss. Vitals for today include BP of 165/100 mm Hg, heart rate of 72, afebrile, and respiratory rate of 13. Her past medical history includes obesity, hypertension, heart failure with preserved ejection fraction (HFpEF), depression, seizure disorder, and liver disease with cholestasis. Her home medications include lisinopril 40 mg daily, fluoxetine 40 mg daily, and levetiracetam 1000 mg BID. Which of the following medications would be appropriate for this patient?

A. Xenical

B. Contrave

C. Adipex-P

D. Saxenda

 

 

Answer with rationale:

The correct answer is D.

Obesity is a highly prevalent disease and is generally defined by a body mass index (BMI) > 30. Because of many health risks associated with obesity (i.e. cardiovascular disease, diabetes, stroke, etc.), it is important to help patients make an effort to achieve weight loss and improve overall quality of life. According to the National Institute of Diabetes and Digestive and Kidney Diseases, patients who qualify for weight-loss medications are those with a BMI > 30 or a BMI > 27 with weight-related health problems, such as hypertension or type 2 diabetes. However, it is essential that patients understand these medications are to be used as an adjunct to lifestyle modifications (i.e. diet, exercise, behavioral changes). Before initiating therapy, risk vs. benefit should be considered while taking into account patients’ past medical history, current medications, and drug side effect profile. This question aligns with NAPLEX Competency Statement 1.2.8: Contraindications, warnings, and precautions.

As pharmacists, it is also important to identify medications that could be contributing to weight gain. Some drug classes that are more commonly associated with weight gain include insulin, sulfonylureas, thiazolidinediones, antidepressants (i.e. amitriptyline, paroxetine, etc.), and antipsychotics (i.e. olanzapine).

Answer A is incorrect. This patient is not a candidate for Xenical (orlistat) because its use is contraindicated in pregnancy, chronic malabsorption syndrome, and cholestasis. Orlistat impairs fat absorption through inhibition of gastric and pancreatic lipases. An important thing to note is that orlistat is available as a prescription medication (Xenical 120 mg) and over the counter medication (Alli 60 mg). Alli has a specific maximum dose of 180 mg per day. Orlistat should be taken during or up to 1 hour after a high-fat meal, and the dose should be omitted if a meal is missed or low in fat. A multivitamin containing fat-soluble vitamins is often recommended (orlistat can decrease absorption of fat-soluble vitamins) and should be separated from orlistat by at least 2 hours. Side effects include oily rectal leakage, flatulence with discharge, increased urinary oxalate levels, and may also increase risk of cholelithiasis.

Answer B is incorrect. Contrave (naltrexone and bupropion) is contraindicated in chronic opioid use, uncontrolled hypertension, history of seizure disorder, bulimia or anorexia, use during or within 14 days following monoamine oxidase inhibitors (MAOIs), pregnancy, and abrupt discontinuation of alcohol, benzodiazepines, barbiturates, and antiepileptic drugs. Initiation is also contraindicated in patients receiving linezolid or intravenous methylene blue. Because this patient has a past medical history of seizure disorder, it would not be appropriate to initiate Contrave. Naltrexone is an opioid antagonist and bupropion is a weak inhibitor of the neuronal reuptake of dopamine and norepinephrine. However, the mechanism in promoting weight loss is not fully understood. The dose is usually titrated over 4 weeks to a maintenance dose of naltrexone 16 mg/bupropion 180 mg BID with a maximum dose of naltrexone 32 mg/bupropion 360 mg/day. Contrave should not be taken with high fat meals. Because of the bupropion component, Contrave comes with a black box warning for increased risk of suicidal ideation in patients < 24 years old with major depressive disorder (MDD) and/or psychiatric disorder. Adverse effects include nausea, constipation, insomnia, hepatotoxicity, and increased blood pressure.

Answer C is incorrect. Adipex-P (phentermine; also available under the brand name Lomaira) is contraindicated in patients with a history of cardiovascular disease, hyperthyroidism, glaucoma, agitated states, history of drug abuse, use during or within 14 days following MAOIs, pregnancy, and breast-feeding. Phentermine is a sympathomimetic amine that promotes weight loss by suppressing appetite, and it is only FDA-approved for short-term use in adjunct to lifestyle modifications. Its stimulant effect is similar to amphetamines, and side effects include palpitations, hypertension, tachycardia, insomnia, and dry mouth. Additionally, our patient's blood pressure is elevated at this time and would require better control.

Answer D is correct. Saxenda (liraglutide) is contraindicated in patients with a history of or family history of medullary thyroid carcinoma (MTC), multiple endocrine neoplasia syndrome type 2 (MEN2), and pregnancy (Saxenda only). Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist and is available as a subcutaneous injection under the brand names Saxenda and Victoza. Saxenda is specifically FDA-approved for obesity, while Victoza is used for the treatment of type 2 diabetes. It is important to note that the usual maintenance dose for Saxenda (3 mg daily) is much higher than Victoza (1.8 mg daily). Adverse effects include nausea, diarrhea or constipation, increased heart rate, and injection site reactions.

See everyone next week!

Dr. B

Christopher M. Bland

Clinical Associate Professor, University of Georgia College of Pharmacy

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