Weight Loss Medications - The Fat Blocker
by Phillip Treadwell, PharmD

 

Orlistat (Xenical®) is a prescription product produced and marketed by Hoffmann LaRoche, better known as Roche. This product is the only prescription agent available that works by decreasing the absorption of fat from the gastrointestinal tract. Because of this mechanism of action, it is sometimes referred to as a “fat blocker”. This product has some real benefits and drawbacks that you should be familiar with before you consider taking it. Hopefully, this summary will help you understand whether or not this product may be right for you.

Orlistat works to decrease the absorption of fat from a meal. To be effective, the medication must be taken with each meal that contains a significant amount of fat. It does not completely block fat absorption, but decreases it by about 30%. Therefore, it will not prevent weight gain from a very fatty meal but will decrease the amount of calories absorbed. This drug has been shown to cause moderate weight loss when combined with diet and exercise. This weight loss is typically not drastic, but is somewhat better than that caused by diet and exercise alone. Orlistat can improve blood sugar levels in diabetics. This improvement in blood glucose is probably related to weight loss and decreased calorie intake. This drug is not absorbed from the gastrointestinal tract, so it is usually considered to be quite safe.

This medication is not without drawbacks, however. When it is taken with a high fat meal, it can cause greasy stools, intestinal gas and pain, and even a loss of bowel continence. This can be quite disconcerting, and causes a fair number of people to stop taking the medication. For some people, this might actually be beneficial in that it can help teach proper eating habits by causing distress with high fat meals. However, it is not effective in blocking sugar absorption, so, low fat, high carbohydrate snacks will still cause just as much weight gain as usual. It does not decrease appetite, and is an easy drug to cheat with because it must be taken with every meal. There are also concerns about decreased absorption of fat soluble vitamins and drugs.

Orlistat is not a panacea. It is expensive, must be taken frequently and can cause troublesome side effects. However, it is a rational drug for people who are significantly overweight, are motivated to change their eating and exercise behaviors, and who just need a little jump start. The benefits of improved weight, blood sugar and perhaps, improved eating habits can be very worthwhile for many people. If you think that you would like to try orlistat, then talk to your physician about the benefits and risks. Working together, you can decide if it is right for you.