Weight Loss Drugs: How Do They Weigh In?

Not happy with your weight?  Tried everything under the sun to lose weight, but just can’t seem to get to that happy place?  Your situation is quite common, and as people age their bodies go through metabolic and hormonal changes which also affect their weight.  Not only does this make it harder to lose, but the body is more prone to gaining.  These days there is a lot of hype about supplements that are marketed for weight loss, as they are not regulated by the Food and Drug Administration (FDA) and you are not required to have a prescription to take one.

As many people turn to supplements to help their weight loss effort, I have not seen many patients who personally state success stories from the supplements they take that are marketed for weight loss.  Not only that, but there is the concern for safety, as supplements and herbal concoctions contain multiple ingredients that can interact with your prescription medications.  Bottom line:  Always tell your doctor and your Registered Dietitian if you are taking any supplements.  Now what about those medications out there?  And when is it right to take one?

As a Registered Dietitian, we promote weight loss through diet, physical activity and behavior change first.  Making small changes at a time and working on lifestyle modifications over time has shown to be very successful for weight loss.  I always tell my patients that slow and steady wins the race!

It is recommended to try for weight loss through a combination of low-calorie/low-fat diets, increased physical activity, and behavior modification first for at least 6 months, then if you are unsuccessful, a medication may be appropriate depending on your weight, risk factors and other health issues.

Generally, weight loss medications are only indicated for individuals with a BMI of 30 or greater.  Some individuals with a BMI of 27 may be prescribed one if they have other factors that increase their health risk, such as diabetes or heart disease.  Recently, the FDA approved 2 more medications on the market.  Here’s the scoop on some medications out there, and a little about how they work in your body.…

alli®:  Manufactured by Glaxosmithkline and approved in 2007 by the FDA as the first over-the-counter weight loss drug, these 60 mg tablets are a lesser dose of the prescription form of orlistat, Xenical® (Roche pharmaceuticals).  Both alli® and Xenical® are brand names for the generic drug, orlistat.  They work by inhibiting some of your body’s fat absorption in the gut by blocking some action of the enzyme, lipase (which breaks down fat).

However, if not taken properly with following a low-fat diet, this can lead to unwanted gastrointestinal side effects, which tend to cause many people to stop taking the drug.  While taking a form of orlistat, it is important to take a multivitamin (usually at bedtime), since the drug may cause some essential fat soluble vitamins to be excreted in the stool.  alli® is taken 3x a day with meals, but should not be taken by certain populations.  For instance, if you have absorption problems, or are on blood thinners, this drug may cause problems.  Remember that this drug works in the gut to block fat absorption, but if your meals do not contain any fat, it really won’t be doing you any good to take it.  It is important to maintain a balanced diet.1

Phentermine:  (one brand name is Adipex® by Gate pharmaceuticals), these tablets are meant for short-term use.  The drug works on your body by decreasing your appetite, and it is meant for short-term management of obesity.  This drug is usually taken once daily earlier in the day.  One problem with long-term effectiveness of this medication is that your body starts to build tolerance to it, and eventually it does not work as effectively on lowering your appetite.  There are some cases in which stopping treatment causes people to overeat to an extent that any weight lost is regained.  This drug is not meant for people with heart disease or hypertension.2

Qsymia®:  Manufactured by Vivus pharmaceuticals, this recently FDA approved weight loss drug is actually a combination of phentermine as well as a drug called topiramate (brand name Topamax® by Janssen pharmaceuticals) which is prescribed for seizures or migraine prevention.  If your doctor prescribes Qsymia®, you will start out with a lower dose at first, and then it will be increased.  This drug is meant to be effective for weight loss because it decreases your thoughts about food and alcohol.  The combination of phentermine and topiramate has a synergistic effect on your body.  As this drug acts on your central nervous system, it may affect your ability to concentrate, and another common side effect is insomnia.3

Additionally, Belviq® developed by Arena pharmaceuticals (generic: lorcaserin HCl) was recently FDA approved in 2012 as a weight loss drug, and it acts on the brain to affect appetite and feelings of fullness.4  There are other weight loss drugs currently undergoing clinical trials in anticipation of future FDA approval.  While all of these new developments are important advancements in science, keep in mind that a weight loss drug is not a cure, but another tool to help you achieve your goals.

It is a common misconception among patients that a weight loss drug will be the quick fix, but these tools are meant to be used in combination with diet, activity, and lifestyle changes.   Most importantly, they are meant to be taken safely.  Your weight loss is centered around what works for you personally and what fits in with your lifestyle.  If you and your doctor determine one of these medications is right for you after unsuccessful weight loss attempts, consult with a Registered Dietitian to help you put your other tools in place for long-term success.

©Adrienne Hatch, MS, RD, LD/N

1Glaxosmithkline.  alli.  Available at:  http://www.myalli.com.  Accessed October 13, 2012.

2National Center for Biotechnology Information, U.S. National Library of Medicine.  Phentermine.  Available at:  http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000605/.  Accessed October 19, 2012.

3Vivus.  Qsymia.  Available at:  http://www.qsymia.com/.   Accessed October 18, 2012.

4U.S. Department of Health and Human Services.  U.S. Food and Drug Administration news release.   FDA approves belviq to treat some overweight or obese adults.  June 27, 2012.  Available at: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm309993.htm.  Accessed October 20, 2012.


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