Sunday, July 15, 2012

Weight loss drug lorcaserin coming soon

Weight loss drug lorcaserin coming soon

The new weight loss drug, lorcaserin will be available in the ensuing months.
But just how safe and effective is lorcaserin?

And what is lorcaserin and how does it work?

The body chemical called serotonin serves many functions. Serotonin has an important role in appetite.  Serotonin like most body chemicals acts by sticking to a receptor on the surface of a cell.
After that binding to the receptor, a whole setting of changes or signals will occur. 

chemical structure of lorcaserin

Lorcaserin reduces appetite but does not increase metabolism or burning up of calories.

Previous drugs fenfluramine and dexfenfluramine also worked through serotonin and were quite effective with weight loss. Those drugs acted on different serotonin receptors, 5-HT2B , and in doing so, caused heart valve abnormalities in a significant percentage of people.

A small percentage of patients on fenfluramine and dexfenfluramine also developed increases in blood pressure in their lungs. This is called pulmonary hypertension.
Fenfluramine and dexfenfluramine were removed from the U.S. market in 1997 because of these adverse effects.

Lorcaserin binds to a different serotonin receptor, the 5-HT2c receptor.
Lorcaserin does not appear to have effects on heart valves or pulmonary artery pressure after 2 years of use.

Lorcaserin side effects include headache, dizziness and nausea. You would expect nausea in any drug that reduces appetite. 
Only about 7 % stopped participation in the studies because of side effects. No liver or kidney problems have been seen with lorcaserin. Quality of life reports were significantly better in those on lorcaserin.

But how effective is lorcaserin for weight loss?

In the 1 year BLOSSOM trial of 4008 adults, on the dose of 10 milligrams twice a day, 35% of participants lost 10% of their weight as compared to only 16% on placebo. The average weight loss in this trial on lorcaserin 10 milligrams twice a day was 8% of body weight as compared to 4% with placebo.

When lorcaserin is stopped weight regain is more likely to occur.
That is as expected.
Drugs don't work when you don't take them and obesity is not curable with a drug like pneumonia is with antibiotics.

But weight regain can occur even if lorcaserin is continued. In the earlier BLOOM trial of 3182 adults, of those who lost 5% of their weight at 1 year, 68% maintained that loss at 2 years if they stayed on lorcaserin while 50% maintained that weight loss at 2 years if they were switched to placebo after 1 year of lorcaserin.

In the BLOSSOM trial, those taking lorcaserin had small improvements in blood pressure (3%), triglycerides (9%) and HDL cholesterol (6%). And high sensitivity CRP and heart rate dropped slightly, both good signs.

How about diabetes? About 90% of people with Type 2 Diabetes are overweight. 
Even modest weight loss can be very helpful in improving blood sugars.
In the just published BLOOM-DM trial, 604 adults with Type 2 Diabetes were randomized to placebo or lorcaserin and followed for 1 year.

In BLOOM-DM, at the beginning of the study, all were taking either metformin or sulfonylurea or both for treatment of their diabetes. The average HgbA1c was 8.1% at baseline.
An average of 5.5% weight loss was seen on lorcaserin as compared to 1.7% on placebo.  Of those completing this 1 year trial, 45% on lorcaserin versus 18% on placebo achieved 5% weight loss. And 20% on lorcaserin vs. 6% on placebo achieved 10% weight loss at 1 year.

Many more patients on lorcaserin got to a HgbA1c of 7% or less than those on placebo: 50% versus 26%.

So lorcaserin looks like it could be helpful for overweight or obese adults. But there is no predicting how a person might do with lorcaserin. Some persons may have a great response while others may find it unhelpful. Lorcaserin would seem most appropriate when the excess weight is contributing to other significant medical problems like sleep apnea or diabetes.

And everyone working on weight loss needs to consciously take steps to increase activity and reduce calories.

Lorcaserin will be marketed in the U.S. as Belviq.
Belviq is no miracle drug but it's a step in the right direction for all those suffering with obesity.
It will be good to have this option available.


  1. Hi Dr. Weiss,

    I was just speaking with you on Avvo regarding the weight gain issue. Are any of these drugs available by prescription or over the counter? Are there any prescription drugs I can ask my doctor for that will burn calories? I don't think I have a problem with appetite reduction (it's very minimal), but my body is definitely barely burning any calories at all.

  2. These agents for weight loss, Belviq and Qsymia, will be available in the coming months by prescription only. There are no agents that safely increase the amount of calories you would burn. That is up to each of us to work hard on being more active.

  3. Thanks for the info. So what does Qsymia do? Is it an appetite reducer like Belviq? I read and reread the article, but couldn't seem to find anything about it. Sorry, if you already addressed that. And is appetite reduction the only effect of Belviq? And what are your thoughts about drugs such as Alli that block the storage of fat? Sorry, for all the questions, but this is just very interesting.

  4. Qsymia reduces appetite too. It contains topiramate and phentermine.Belviq only works by reducing appetite. Alli blocks absorption (not storage) of fat. You excrete more fat in the stool with the Alli than you do without the Alli. Alli does not affect appetite. Thanks for the good questions.

    1. I see. I can't wait until these are released. I'm definitely be going to talking to my doctor about this. And you're welcome, and thanks so much for answering my questions!