science

Lorcaserin

Lorcaserin is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Lorcaserin rather than just read about it. In short: Lorcaserin, marketed under the brand name Belviq, was a weight-loss drug developed by Arena Pharmaceuticals. It reduces appetite by activating the 5-HT2C serotonin receptor in the hypothalamus, a region of the brain which is known to control appetite.

Key takeaways

Lorcaserin belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Lorcaserin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Lorcaserin from memory before moving on to harder problems.

Reference excerpt

Lorcaserin, marketed under the brand name Belviq, was a weight-loss drug developed by Arena Pharmaceuticals. It reduces appetite by activating the 5-HT2C serotonin receptor in the hypothalamus, a region of the brain which is known to control appetite. It was approved in 2012, and in 2020 was removed from the market in the United States due to an increased risk of cancer detected in users of Belviq.

Medical uses Lorcaserin was used long term for weight loss in those who are obese. The safety and efficacy of Belviq were evaluated in three randomized, placebo-controlled trials that included nearly 8,000 obese and overweight patients, with and without type 2 diabetes, treated for 52 to 104 weeks. All participants received lifestyle modification that consisted of a reduced calorie diet and exercise counseling. Compared with placebo, treatment with Belviq for up to one year was associated with average weight loss ranging from 3 percent to 3.7 percent. About 47 percent of patients without type 2 diabetes lost at least 5 percent of their body weight compared with about 23 percent of patients treated with placebo. In people with type 2 diabetes, about 38 percent of patients treated with Belviq and 16 percent treated with placebo lost at least 5 percent of their body weight. Belviq treatment was associated with favorable changes in glycemic control in those with type 2 diabetes. The approved labeling for Belviq recommends that the drug be discontinued in patients who fail to lose 5 percent of their body weight after 12 weeks of treatment, as these patients are unlikely to achieve clinically meaningful weight loss with continued treatment. The drug's manufacturer was required to conduct six postmarketing studies, including a long-term cardiovascular outcomes trial to assess the effect of Belviq on the risk for major adverse cardiac events such as heart attack and stroke.

Side effects There had been concern that lorcaserin could cause cardiac valvulopathy based upon the reports of subjects taking the drug in Phase 2 trials. However, a 2016 Phase 3 clinical trial found no statistically significant differences in valvulopathy rates compared to control, being 2.4% for the drug subjects and 2.0% for controls, and concluded that the drug was safe for the target population although more long-term data was needed. FDA required a post-marketing cardiovascular safety trial as a condition of lorcaserin's approval (a requirement for all weight management drugs since the withdrawal of sibutramine in 2010 due to cardiovascular harm). The CAMELLIA-TIMI 61 trial was conducted for this purpose, and it showed no difference in rates of major adverse cardiovascular events ("MACE+", a composite of "cardiovascular death, myocardial infarction, stroke, hospitalization for unstable angina, heart failure, or any coronary revascularization") between lorcaserin and placebo. However secondary analysis of CAMELLIA-TIMI 61 by FDA showed a likely higher cancer risk in those taking lorcaserin. The trial was conducted in approximately 12,000 participants over five years and more patients taking lorcaserin were diagnosed with cancer compared to patients taking placebo. CAMELLIA-TIMI 61 was powered to detect differences in MACE, but was not adequately powered to detect differences in cancer rates over the five-year study period. In February 2020, the FDA requested that the manufacturer of lorcaserin voluntarily withdraw the drug from the US market because a safety clinical trial showed an increased occurrence of cancer. The drug manufacturer, Eisai, voluntarily withdrew the drug.

Overdose Lorcaserin can produce hallucinogenic effects and other side effects with overdose. This can occur with single doses that are only 2- to 6-fold the usual single therapeutic dose. The effects are thought to be serotonergic psychedelic effects and are believed to be mediated by activation of the serotonin 5-HT2A receptor.

Pharmacology

Pharmacodynamics

Lorcaserin is a selective 5-HT2C receptor agonist, and in vitro testing of the drug showed reasonable selectivity for 5-HT2C over other related targets. 5-HT2C receptors are located almost exclusively in the brain, and can be found in the choroid plexus, cortex, hippocampus, cerebellum, amygdala, thalamus, and hypothalamus. The activation of 5-HT2C receptors in the hypothalamus is supposed to activate proopiomelanocortin (POMC) production and consequently promote weight loss through satiety. This hypothesis is supported by clinical trials and other studies. While it is generally thought that 5-HT2C receptors help to regulate appetite as well as mood, and endocrine secretion, the exact mechanism of appetite regulation was not known as of 2005. Lorcaserin has shown 100x selectivity for 5-HT2C versus the closely related 5-HT2B receptor, and 17x selectivity over the 5-HT2A receptor.

Pharmacokinetics The elimination half-life of lorcaserin is approximately 11 to 12 hours.

Chemistry Lorcaserin is a substituted 3-benzazepine derivative. The chemical structure of lorcaserin is similar to that of para-chloroamphetamine (PCA). It is also similar to that of 7-AB.

History

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Lorcaserin

Start with the simplest possible case. Write down what Lorcaserin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Lorcaserin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Lorcaserin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Lorcaserin

In research: Lorcaserin appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Lorcaserin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Lorcaserin is common in secondary-school and first-year university syllabi. It links to neighbouring topics 5-HT2A agonists, 5-HT2B agonists, 5-HT2C agonists, so understanding it makes those chapters shorter.
In everyday life: Look for Lorcaserin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Lorcaserin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lorcaserin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Lorcaserin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lorcaserin in simple terms?

Why does Lorcaserin matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Lorcaserin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Lorcaserin.