Current Status of Obesity and Weight Loss Medications

As per the World Health Organization, approximately 13% of adults worldwide were obese in 2016. Obesity greatly increases the risks of various chronic diseases like diabetes, heart diseases, and certain cancers. Lifestyle changes through diet and exercise remain the first-line approach for sustainable weight management. However, long-term adherence can be challenging and additional therapies are often needed. Weight loss medications, also known as anti-obesity drugs, have emerged as an effective medical intervention for chronic weight management in obese individuals.

Types of FDA Approved Anti-Obesity Medications

Currently, there are 5 types of Anti-Obesity Drugs approved by the US Food and Drug Administration (FDA) for long-term weight management in obese adults.

1. Orlistat: Orlistat is a lipase inhibitor that works by preventing the absorption of around 30% of the fat consumed from the diet in the gastrointestinal tract. It mainly leads to loss of excess calorie intake and results in modest weight loss.

2. Lorcaserin: Lorcaserin is a selective serotonin 2C receptor agonist that works in the brain to suppress appetite. It has shown to lead to average weight loss of 3-3.7% over 1 year of treatment.

3. Phentermine/Topiramate: This drug contains phentermine, an appetite suppressant, along with topiramate, an anticonvulsant also known to induce weight loss. Clinical trials have reported average weight loss of 9-10% over 1 year with this medication.

4. Naltrexone/Bupropion: This combination drug contains naltrexone, an opioid antagonist, and bupropion, an atypical antidepressant also used as a smoking cessation agent. Studies have shown average weight loss of 6-8% over 1 year with naltrexone/bupropion treatment.

5. Semaglutide: Semaglutide is the first glucagon-like peptide-1 (GLP-1) receptor agonist approved for chronic weight management. It mimics the effects of naturally occurring hormone GLP-1 leading to weight loss of 15% on average over 68 weeks in clinical trials.

Mechanism of Action and Efficacy of Different Drug Classes

Broadly, anti-obesity drugs work via four main mechanisms – suppressing appetite, decreasing fat absorption, altering fat metabolism, or inducing satiety/fullness. Orlistat belongs to the latter class by preventing absorption of dietary fat in the gut. Lorcaserin, phentermine/topiramate and naltrexone/bupropion suppress appetite centrally in the brain. Semaglutide induces satiety and alters fat metabolism by mimicking GLP-1 hormone actions in the body.

In terms of efficacy, results from randomized controlled trials indicate average weight loss ranging from 3-15% of initial body weight over 1 year based on the drug class. Orlistat leads to the lowest average weight loss of 3-6% whereas semaglutide achieves significantly higher loss of 15% up to 2 years. Phentermine/topiramate and naltrexone/bupropion also produce appreciable loss of 9-10% and 6-8% respectively over 12 months. Lorcaserin results in modest 3-3.7% weight reduction during the same duration.

Safety and Tolerability of Anti-Obesity Medications

Despite proven efficacy for inducing weight loss, safety continues to be a major concern with anti-obesity drugs. All approved drugs are generally well-tolerated but commonly reported side effects include gastrointestinal issues like oily spotting, flatulence with orlistat use. Lorcaserin may cause headache, nausea, and dizziness. Phentermine/topiramate is associated with paresthesia, constipation, and altered taste. Rare but severe side effects of heart valve problems and pulmonary hypertension have been reported with fenfluramine and dexfenfluramine components previously used in obesity medications. Overall, physicians must carefully evaluate risk-benefit profile for each individual patient before prescribing anti-obesity medications. Close monitoring is warranted during treatment as well.

Place of Anti-obesity Drugs in Comprehensive Weight Management

They are not intended for short-term use or as standalone therapies but as an adjunct to lifestyle modifications on a long-term basis for clinically obese individuals. For most effective and sustainable results, the current clinical practice guidelines recommend lifestyle interventions involving reduced-calorie diet and increased physical activity combined with behavioral modification therapies. Anti-obesity drugs can then be added as a supplementary treatment option based on individual risk factors, comorbidities and intended weight loss goals to boost outcomes achieved through lifestyle measures alone. Overall, weight loss achieved through a multimodal approach incorporating medical weight management using anti-obesity drugs along with lifestyle and behavioral therapies has demonstrated most promising long-term success in chronic obesity treatment and management over the years.

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Ravina Pandya, Content Writer, has a strong foothold in the market research industry. She specializes in writing well-researched articles from different industries, including food and beverages, information and technology, healthcare, chemical and materials, etc. (https://www.linkedin.com/in/ravina-pandya-1a3984191)