Anti-obesity medication

An overview of medications used to treat obesity

Anti-obesity medications in various forms

Anti-obesity medications are pharmacological agents that aid in reducing or controlling body weight. These medications alter one of the fundamental processes of the human body, weight regulation, by either reducing appetite, inhibiting the absorption of calories, or increasing energy expenditure.

Anti-obesity medications are often used in conjunction with lifestyle interventions, such as diet and exercise, to achieve and maintain weight loss. They are typically recommended for individuals with a body mass index (BMI) of 30 or greater, or 27 or greater with comorbid conditions such as type 2 diabetes or hypertension.

Mechanism of Action

Anti-obesity medications function through various mechanisms:

• Appetite suppression: Some medications work on the central nervous system (CNS) to suppress appetite by influencing neurotransmitters such as serotonin, norepinephrine, and dopamine. These changes can lead to reduced food intake.

• Inhibition of Fat Absorption: Certain medications, such as orlistat, inhibit the absorption of dietary fats in the intestine, reducing the number of calories absorbed by the body.

• Increased Energy Expenditure: Some drugs aim to increase the body's metabolic rate, thereby increasing energy expenditure and contributing to weight loss.

• Glucagon-like Peptide-1 (GLP-1) Receptor Agonists: GLP-1 analogues, such as semaglutide and tirzepatide, mimic the action of the naturally occurring GLP-1 hormone to increase insulin secretion, reduce appetite, and slow gastric emptying.

Common Medications

Several medications are commonly used in the treatment of obesity. These include both prescription medications and GLP-1 receptor agonists:

• Orlistat: A lipase inhibitor that works by blocking the enzyme lipase, which is responsible for breaking down dietary fats in the intestine. This results in reduced fat absorption.

• Phentermine: An appetite suppressant that stimulates the release of norepinephrine in the brain, leading to decreased appetite. It is often used for short-term weight loss.

• Lorcaserin: A serotonin receptor agonist that promotes satiety by activating the serotonin 2C receptor in the brain, reducing hunger and increasing feelings of fullness. This drug, marked under brand name Belviq, was withdrawn from the United States market.

• Liraglutide: A GLP-1 receptor agonist that mimics the effects of the GLP-1 hormone. It increases insulin secretion, decreases appetite, and promotes a feeling of fullness.

• Semaglutide: Another GLP-1 receptor agonist that has gained attention for its effectiveness in promoting weight loss. Semaglutide not only reduces appetite but also improves glycemic control in individuals with type 2 diabetes.

• Tirzepatide: A newer medication that combines GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptor agonists. Tirzepatide has shown promising results in reducing weight and improving blood sugar levels.

Experimental Drugs

Several experimental drugs are being tested for their potential to treat obesity. These drugs have not yet received approval from regulatory authorities, but they represent the future of obesity treatment:

• Setmelanotide: A melanocortin-4 receptor (MC4R) agonist that has been shown to be effective in individuals with genetic obesity disorders, such as POMC deficiency, by influencing the brain's appetite-regulating pathways.

• Cagrilintide: A long-acting amylin analogue that works by reducing hunger and increasing satiety. It is often studied in combination with other medications, such as semaglutide, to enhance weight loss effects.

• Bimagrumab: A monoclonal antibody that targets the activin receptor type IIB, which is involved in muscle growth. Bimagrumab has shown potential in reducing body fat and increasing lean muscle mass in early trials.

Side Effects

The use of anti-obesity medications can be associated with various side effects. These may include:

• Gastrointestinal Issues: Common side effects include oily stools, diarrhea, and flatulence, particularly with fat absorption inhibitors like orlistat.

• Cardiovascular Effects: Medications like phentermine and lorcaserin may cause increased heart rate and blood pressure.

• Central Nervous System Effects: Some medications can lead to side effects such as insomnia, nervousness, dizziness, and headaches.

• Endocrine Effects: GLP-1 receptor agonists such as liraglutide, semaglutide, and tirzepatide may cause nausea, vomiting, or abdominal discomfort as the body adjusts to the medications.

Considerations and Contraindications

The prescription of anti-obesity medications requires careful consideration of the patient's overall health, potential side effects, and contraindications. These medications should not be used by individuals with certain conditions, such as severe cardiovascular disease, or by pregnant or breastfeeding women. A thorough medical evaluation is necessary before starting any anti-obesity medication.

Obesity medications are typically recommended for those who have not been able to achieve sustained weight loss through lifestyle changes alone, such as diet and exercise.

Related Pages

• Obesity
• Body mass index
• Dieting
• Physical exercise
• Type 2 diabetes
• Hypertension