15 July 2013

Belviq: the new miracle diet drug?

A new pharmaceutical slimming product known as Belviq has been approved by the FDA in the US. Does it work and is it safe?

The media is abuzz with news that a new pharmaceutical slimming product known as Belviq has at last been approved by the FDA in the US (Nair, 2013; Perrone, 2012).

It has been 13 long years since orlistat (Xenical, Alli) was approved by the FDA and in this period most of the other pharmaceutical slimming pills that were available, have been discontinued or banned, leaving obese and overweight patients with only a limited choice.

Understandably those South Africans who want or need to lose weight, want to be able to purchase Belviq sooner, rather than later.

The long wait

Ever since "legitimate" or pharmaceutical slimming pills such as Reductil were withdrawn from the market in South Africa more than two years ago, individuals who are desperate to lose weight and require some assistance to slim down, have only been able to use orlistat (Xenical or Alli), which prevents the uptake of fat from the diet and thus reduces energy intake leading to weight loss (Nair, 2013).

Needless to say, there are countless (at least one or more a week) over-the-counter slimming pills and potions that are being launched in South Africa all the time, but the majority of these products either do not contain any active ingredients or do contain potentially harmful components. South African slimmers like their counterparts in the rest of the world (Perrone, 2012), have consequently been waiting for pharmaceutical companies to come up with new prescription drugs that will promote weight loss and/or suppress the appetite.

The dream has now come true in the USA, but Belviq is alas still not available in South Africa. We also do not know how long it will take for this product to be approved by the South African Medicines Control Council (SAMCC) for use in this country. In the meantime, government bodies such as the SA Revenue Services have already sounded a warning that any medicines from overseas which are ordered over the internet will be intercepted by SARS customs officers and handed over to the health authorities (Nair, 2013). 

What can we expect from Belviq?

While overweight and obese South Africans wait for the wheels of government to turn ever so slowly to legitimise the sale of this new prescription diet drug in South Africa (and it may take years!), it is interesting to read the package insert information for Belviq that is available on the internet (DailyMed, 2013).

Belviq contains a chemical compound called lorcaserin hydrochloride, which is a so-called serotonin 2C-receptor agonist.

Serotonin is a chemical produced in the brain and other organs of the human body, which affects mood and appetite. A deficiency in serotonin has been linked to manifestations such as depression, low self-esteem, insomnia, panic attacks, eating disorders, anxiety, food cravings and overeating to name but a few.

Various drugs have been developed to increase serotonin levels in the brain to combat the above mentioned symptoms. Lorcaserin is one of these drugs which can increase serotonin levels and thus reduce appetite which when used in conjunction with an energy-reduced diet and exercise should lead to weight loss.

Belviq was developed by Arena Pharmaceuticals in the USA, and its indications specifically state that it is to be used as "an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults" who are overweight (BMI of 27 kg/m2 or greater) or obese (BMI of 30 kg/m2 or greater), "in the presence of at least one weight-related comorbid condition (e.g. hypertension, dyslipidemia, type 2 diabetes)" (DailyMed, 2013). 

This means that someone who just wants to lose a few kilos or overweight patients who are otherwise healthy with no high blood pressure, raised blood fats or type 2 diabetes, do not meet the requirements or indications for the prescription of Belviq.

There is also the added caution that if "5% of weight loss is not achieved by week 12" the drug should be discontinued.

Patients, therefore, need to be seriously overweight and afflicted with additional complications of obesity before they can be considered for prescription of Belviq and they are also supposed to reach the goal of losing 5% of their body weight within 3 months to be allowed to continue using this drug.

An obese patient weighing 100kg would therefore have to lose 5kg in 3 months to stay on the drug.

This should basically be an achievable goal, but the question arises if it is necessary to use a drug to achieve this type of weight loss? Could patients weighing in at 100kg not possibly lose 5kg over 12 weeks with diet and exercise alone?

Results achieved

According to a Phase III scientific study called Blossom (Behavioral Modification and Lorcaserin Second Study for Obesity Management), an average weight loss of 5.8% of initial body weight on lorcaserin 10mg twice a day was achieved versus a weight loss of 2.8% of initial body weight on placebo.

The Blossom study set out to determine the effects of lorcaserin on body weight, cardiovascular risk factors and safety in 4 008 patients (aged 18-65 years) with a BMI between 30 and 45 kg/m2 (obese) or between 27 and 29.9 kg/m2 (overweight) with an obesity-related comorbid condition for one year with a randomised, placebo-controlled design at 97 research centres in the USA.

A total of 47.2% of the lorcaserin-treated patients lost at least 5% or more of initial body weight compared with the 25% of placebo-treated patients who achieved a 5% or greater weight loss. Some patients achieved more than 5% losses, with up to 22% on lorcaserin losing 10% or more of their initial body weight compared to 9.7% of the placebo-group (Fidler et al, 2011).

On average, the patients who received lorcaserin lost 5.9% of their initial body weight or 5.7kg, while the placebo groups lost an average of 2.8% or 2.9 kg.

Similar results were also obtained in the Bloom-DM study (Behavioral Modification and Lorcaserin for Overweight and Obesity Management - Diabetes Mellitus), where 37.5% of the lorcaserin-treated diabetic patients with weight issues lost 5% or more of their initial weight versus 16.1% of the placebo-treated overweight/obese diabetics (O’Neil et al, 2012).


The following side-effects were reported for patients participating in these studies and receiving treatment with lorcaserin:
headache, back pain, nausea, and dizziness (Fidler et al, 2011; O’Neil et al, 2012)
Specific investigations were also carried out to monitor potential cardiac problems (valvulopathy or dysfunction of the heart valves), because a number of earlier pharmaceutical slimming drugs had been discontinued because of their negative effect on the cardiovascular system.

In the Blossom trial, the incidence of valvulopathy as detected by serial echocardiograms to track heart valve function, found an identical 2.0% incidence of this disturbance in patients on placebo and patients receiving lorcaserin 10mg twice daily (Fidler et al, 2011). It would, thus appear that the incidence of these heart valve problems did not increase when patients used lorcaserin for weight loss.
A meta-analysis of trials using lorcaserin by Chan and coworkers (2013) concluded that "lorcaserin achieves modest weight loss and appears to be well tolerated. Clinical and pharmacovigilance studies with longer study duration are need to inform of the long-term efficacy and safety of lorcaserin".


It would seem that lorcaserin or Belviq does hold promise for modest to good weight loss ranging from 5 to 10% of body weight when combined with an energy-reduced diet and exercise. South African slimmers will, however, have to wait until this drug has been approved by the SAMCC, so a great of patience will be required.

In the meanwhile, obese or overweight patients should consider using balanced energy reduction and exercise (as approved by your physician especially if you suffer from one or more of the so-called comorbidities of obesity) to work towards your goal of weight loss. Discuss the use of the one drug that is available in South Africa, namely orlistat, with your doctor or dietitian if you need additional support.
(References: Chan EW et al (2013). Efficacy and safety of lorcaserin in obese adults: a meta-analysis of 1-year randomized controlled trials (RCTs) and narrative review on short-term RCTs. Obes Rev, 14(5):383-92; DailyMed (2013). Belviq (Lorcaserin hydrochloride) Tablet.;  Fidler MC et al (2011). A one-year randomized trial of lorcaserin for weight loss in obese and overweight adults: the BLOSSOM trial. J Clin, Endocrinol Metab, 96(10):3067-77; Nair N (2013). Big demand for ‘legit’ diet drug. The Times, Published on 11 July 2013, page 6; O’Neil PM et al (2012). Randomized placebo-controlled clinical trial of lorcaserin for weight loss in type 2 diabetes mellitus: the BLOOM-DM study. Obesity, 20(7):1426-36; Perrone M (2012). Belviq: First new weight-loss pill approved by FDA in decade. Huffpost Healthy Living, Published on 14 July 2013.

 - (Photo of pill on fork from Shutterstock)


Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Read more of her articles.


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