Belviq, with the generic name lorcaserin, was a prescription medication developed for chronic weight management in adults who are obese or overweight. Approved by the FDA in 2012, Belviq was intended to be used alongside a reduced-calorie diet and increased physical activity. The drug was specifically indicated for adults with a body mass index (BMI) of 30 kg/m² or greater (obese), or 27 kg/m² or greater (overweight) with at least one weight-related health condition such as hypertension, dyslipidemia, or type 2 diabetes.

Mechanism of Action

Belviq works by targeting serotonin 2C (5-HT2C) receptors in the hypothalamus, a part of the brain that regulates appetite. By activating these receptors, Belviq helps reduce feelings of hunger and increases satiety, making it easier for individuals to eat less and lose weight. Unlike older weight-loss drugs, Belviq was designed to selectively target only the serotonin receptors involved in appetite, minimizing effects on mood or other bodily functions.

Effectiveness

Clinical trials involving nearly 8,000 overweight and obese patients, both with and without type 2 diabetes, showed that Belviq led to modest but significant weight loss when combined with diet and exercise. After one year, patients taking Belviq lost an average of 3–3.7% of their body weight, compared to placebo. About 47% of non-diabetic patients and 38% of diabetic patients taking Belviq lost at least 5% of their body weight, versus 23% and 16% in the placebo group, respectively. Belviq also improved glycemic control in people with type 2 diabetes.

Administration and Limitations

The recommended dosage was 10 mg twice daily, with or without food. Patients were advised to discontinue Belviq if they failed to lose at least 5% of their baseline body weight after 12 weeks, as further significant weight loss was unlikely. The safety and efficacy of Belviq when used with other weight-loss medications were not established, and its effect on long-term cardiovascular outcomes was still under investigation at the time of its approval.

Safety and Side Effects

Common side effects included headache, dizziness, fatigue, nausea, dry mouth, and constipation. In patients with diabetes, hypoglycemia was also reported. Serious warnings included the risk of serotonin syndrome, especially if taken with other serotonergic drugs, and potential for cognitive impairment or psychiatric effects. There were also concerns about valvular heart disease, and patients experiencing symptoms were advised to discontinue the medication and seek evaluation.

Belviq (Lorcaserin): Uses and Mechanism – Subparts

1. Overview and Indications

Belviq, with the generic name lorcaserin, was a prescription medication approved for chronic weight management. It was indicated for use in adults with:

• Obesity (BMI ≥ 30 kg/m²)

• Overweight (BMI ≥ 27 kg/m²) with at least one weight-related comorbidity, such as hypertension, dyslipidemia, or type 2 diabetes.

Belviq was intended to be used as an adjunct to a reduced-calorie diet and increased physical activity for long-term weight control.

2. Mechanism of Action

• Lorcaserin is a selective serotonin 5-HT2C receptor agonist.

• It acts primarily in the central nervous system, especially the hypothalamus, a brain region that regulates appetite and satiety.

• By stimulating 5-HT2C receptors on pro-opiomelanocortin (POMC) neurons in the arcuate nucleus, lorcaserin triggers the release of alpha-melanocortin-stimulating hormone (alpha-MSH). This hormone then acts on melanocortin-4 receptors in the paraventricular nucleus, leading to appetite suppression.

• The selectivity for 5-HT2C over other serotonin receptors (such as 5-HT2A and 5-HT2B) is important, as stimulation of 5-HT2B has been associated with cardiac side effects in older weight-loss drugs.

3. Clinical Effectiveness

• In clinical trials, Belviq led to modest but significant weight loss when combined with lifestyle modifications.

• After one year, patients lost an average of 3–3.7% of their body weight, compared to placebo.

• About 47% of non-diabetic patients and 38% of diabetic patients taking Belviq lost at least 5% of their body weight, compared to 23% and 16% in the placebo groups, respectively.

• Belviq also improved glycemic control in individuals with type 2 diabetes.

4. Dosage and Administration

• The standard dosage was 10 mg taken orally twice daily, with or without food.

• If a patient did not lose at least 5% of their baseline body weight after 12 weeks, discontinuation was recommended as further significant weight loss was unlikely.

5. Pharmacology and Selectivity

• Lorcaserin is highly selective for the 5-HT2C receptor, with much lower affinity for 5-HT2A and 5-HT2B receptors.

• The drug is extensively metabolized in the liver, and its elimination half-life is approximately 11–12 hours.

• It distributes to the central nervous system, which is necessary for its appetite-suppressing effects.

6. Safety and Withdrawal

• Common side effects included headache, dizziness, fatigue, nausea, dry mouth, and constipation.

• At higher doses or overdose, lorcaserin can lose selectivity and bind to other serotonin receptors, potentially causing hallucinogenic effects.

Withdrawal from Market

In 2020, Belviq was withdrawn from the U.S. market after post-marketing studies found an increased risk of cancer in users. The FDA concluded that the potential risks of Belviq outweighed its benefits for weight management, leading to its removal from the market.

Conclusion

Belviq was a serotonin receptor agonist developed to help adults with obesity or overweight conditions manage their weight when combined with lifestyle changes. It worked by reducing appetite and increasing feelings of fullness, resulting in modest weight loss for many patients. However, due to concerns about increased cancer risk, Belviq is no longer available for prescription.