Orlistat, which includes both the prescription drug Xenical and over-the--counter drug Alii, reduce secretion of appetite-reducing hormones in the gut, which could increase appetite according to a new study from researchers at St. Josef-Hospital at Ruhr-University in Bochum, Germany.

After being on store shelves for one year, GlaxoSmithKline said it sold 4 million kits of Alli (orlistat) in the US. Alli is the only over-the-counter weight loss drug approved by the US Food and Drug Administration (FDA).

The over-the-counter fat blocker, Alii (60 mg of orlistat), blocks the absorption of about 25 percent of dietary fat and causes a weight loss of about 5 percent of body weight in the first four months according to a review paper by J. W. Anderson from the University of Kentucky’s College of Medicine in Lexington, Kentucky, USA.

After patients had lost an average of 19.3 pounds with Xenical (orlistat) plus a reduced-calorie diet, half of them continued taking Xenical (120 mg of orlistat) three times per day plus a weight maintenance diet for another year, while the other half of patients were given Alli (60 mg of orlistat) instead. Weight loss at the end of the second year was 12.3 pounds for those who kept taking Xenical (120 mg of orlistat) versus 9.9 pounds for those given Alli (60 mg of orlistat) compared to 6.9 pounds for those who were switched from Xenical to a placebo.

As a physician who has committed the past 15 years of my professional career to the medical treatment of overweight and obese patients, I feel the need to express my concern over Alli, the recently FDA approved OTC “fat blocker”, and with GlaxoSmithKline, the pharmaceutical company who owns it.

Orlistat (Xenical and Alii) is a diet pill that prevents the absorption of approximately one-third of dietary fat. Studies lasting 3 months have found that it increases weight loss by approximately 0.4 lbs per week which is nearly as much as to 0.5 lbs seen with other prescription diet pills, however, it does not reduce appetite like other weight loss medications.

The fat-blocking drug orlistat (Xenical and Alii) increases weight loss by 4-5 pounds in three months according to two studies.

The fat-blocking drug orlistat (Xenical and Alii) works by inhibiting three enzymes involved in the breakdown of dietary fat which allows fat to be absorbed—gastric lipase, pancreatic lipase and pancreatic carboxylester lipase. Pancreatic lipase is the key enzyme required for the absorption of dietary fats. Gastric lipase triggers pancreatic lipase, and pancreatic carboxylester lipase is used in the absorption of fat soluble vitamins.

On Thursday, Feb 7th, 2007, the U.S. Food and Drug Administration (FDA) approved a low-dose version of orlistat capsules as an over-the-counter (OTC) weight loss aid for overweight adults. The drug will be produced by GlaxoSmithKline and called Alii. 

I received an email asking how effective lower doses of orlistat are, such as the 60 mg found in Alii (orlistat), compared to the 120 mg found in the prescription version, Xenical (orlistat). The research shows that 60 mg three times per day is nearly as effective as 120 mg. The research also shows that doses higher than 120 mg three times per day are no more effective.