Dietitians Dish: Get familiar with weight-loss medications

By Stephanie Whitley, RDN, LD
Sept. 24, 2013 at 4:24 a.m.

Stephanie Whitley

Stephanie Whitley

In the last six decades or so, weight-loss medications have been available over the counter and by prescription. Many medications have come and gone because of dangerous side effects such as heart valve changes in some patients who took fenfluramines.

This is not to be confused with phentermine, which is the oldest short-term, weight-loss drug that has been approved by the Food and Drug Administration since the 1960s and has had millions of prescriptions written.

The recommended requirements for Food and Drug Administration approved weight-loss medications to be prescribed are a Body Mass Index of 30 or greater or an Index of at least 27 with an obesity-related problem, such as diabetes, high blood pressure or high cholesterol.

Unfortunately, about 25 percent of the prescriptions written are for people with a BMI less than 27. Weight-loss prescriptions are simply a tool, not a cure, for excess weight. When combined with healthy eating and exercise, one could expect to lose 5-10 percent of their body weight.

This may be less than most would expect, but even a 10 percent weight loss can lead to significant improvement in diseases such as blood pressure, insulin sensitivity, blood sugar control and cholesterol levels.

Weight-loss drugs are not suitable for everyone and, of course, should be discussed in detail with your physician, especially if you are taking over-the-counter supplements for weight loss that are not approved by the FDA.

Orlistat (Xenical), lorcaserin (Belviq) and Qsymia are currently approved for long-term use by the FDA. Orlistat is a prescription strength weight-loss medication; however, you may have also heard of Alli, which is half-strength Orlistat that can be purchased over the counter. Orlistat works by blocking about 30 percent of the fat you eat from being absorbed.

It should be taken around the time of your meal and never with an extra high-fat meal, such as a cheeseburger, fries and milkshake. Side effects are fatty stools, abdominal discomfort, increased number of bowel movements in a day and fecal urgency, which can be very embarrassing at times.

In addition, Orlistat also interferes with the absorption of the fat-soluble vitamins: A, D, E and K. Make sure you are supplementing these vitamins correctly. Lorcaserin (Belviq) works by suppressing your appetite and increasing your sense of fullness by altering chemicals in your brain.

A study revealed that 47 percent of the patients on lorcaserin lost about 5 percent of their body weight in one year. Qsymia is a combination of phentermine, which suppresses your appetite, and topiramate, which is used to treat seizures and migraine headaches. Together, these drugs can increase your feeling of fullness and decrease your desire to eat.

Short-term weight loss prescription drugs that are FDA approved for up to 12 weeks of use are phentermine (Adipex-P, Oby-Cap, T-Diet, Zantryl, Suprenza), phendimetrazine (Adipost, Bontril Slow-Release, Bontril PDM, Melfiat), diethylpropion (Tenuate, Tenuate Dospan) and benzphetamine (Didrex).

Some prescription drugs that are not considered weight-loss drugs, such as metformin and bupropion, can have a side effect of decreased appetite. Be sure you are very familiar with the side effects of any drug you take, especially if you are pregnant or planning to become pregnant.

These medications alone typically do not lead to the desired minimum of 10 percent weight loss. However, when combined with healthy eating and exercise, physician-approved weight-loss prescription drugs can be another tool in achieving a healthy weight to last a lifetime.

Stephanie Whitley is a registered and licensed dietitian at DeTar Healthcare System. Send questions or comments to



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