A slimming pill designed to treat obesity has been found to help people lose weight without increasing their risk of heart problems.

A major clinical trial of weight loss drug lorcaserin found it didn’t increase the risk of heart attack, stroke or death from heart disease among overweight and obese patients.

It also helped them lower their weight by an average of 4.2kgs (9.3 lbs) a year – equating to about two stone in three years.

How does the pill work?

Lorcaserin stimulates a part of the brain which controls how hungry you feel and your body’s metabolism.

Historically, many weight loss agents have impacted the heart negatively, leading to dangerous conditions such as stroke, heart attack, pulmonary hypertension and valvular heart disease. As a result, they were often withdrawn from the market.

But in the latest clinical trial, which involved 12,000 overweight or obese patients at risk of a heart problem, lorcaserin was found to be safe – at least as far as heart health was concerned.

What did the study find?

Study participants were randomly assigned to take either lorcaserin or a placebo and were followed for just over three years. The team found the number of cardiovascular events was roughly the same for both groups.

Furthermore, in addition to lifestyle counselling, the pill helped patients lower their weight by 4.2kgs (9.3lbs) on average in a year. In comparison, the placebo group lost 1.4kgs (3lbs).

The drug also resulted in small improvements in several factors generally associated with cardiovascular disease including levels of triglycerides, blood glucose, heart rate and blood pressure.

Erin Bohula, a cardiovascular medicine and critical care specialist at Brigham and Women’s Hospital, said: “For now, after rigorous testing, we can report that this is the first and only weight loss agent to show long-term cardiovascular safety in a high-risk population.”

Are there any side effects?

The most common side effects of the pill were dizziness, fatigue, headache, nausea and diarrhoea.

Could it be approved in the UK?

Lorcaserin has been available in the US for a while now, however it isn’t approved for use in Europe.

Current treatment of obesity includes dietary and lifestyle advice, pharmacological treatments and surgical intervention, according to the National Institute for Health and Care Excellence (NICE).

A spokesperson said an appraisal of lorcaserin for treating obesity was suspended after the pill’s sponsor Arena Pharmaceuticals withdrew their licensing application to the European Medicines Agency (EMA).

“NICE cannot appraise a product if it is un-licensed, therefore we had to suspend at that point,” they said. “The company has told us it is currently evaluating the best approach for submitting at a later date.”