Weight Loss Pills Needing an Rx

Diet drugs sales are up. A report by market research firm MarketData showed Americans spend over $59 billion a year on weight-loss drugs, but only about 1 percent is spent on prescription weight-loss medication. While over-the-counter weight loss aids, like Alli, attract consumer dollars, the pharmaceutical companies are trying to manufacture a drug that does what it says without the serious side effects of past weight-loss medications like fen-phen.

Meridia

• Sibutramine is the generic name for the diet drug Meridia, which works to alter the chemistry in the body when weight gain is due to diabetes, high cholesterol or high blood pressure. In an article published by the Vanderbilt University Psychology Department, Anjali Shah states that Meridia is a "monoamine (serotonin and norepinephrine) re-uptake inhibitor," similar in class to some antidepressants like Prozac. Meridia works on the serotinin levels to contribute to a feeling of being full, thus lessening the desire to continue to eat. Meridia requires a prescription from a doctor.

  Serious side effects may include fast, pounding heartbeats, dangerously high blood pressure, seizures and blood in the stool. Less serious side effects include dry mouth, upset stomach, dizziness and cold-like symptoms.

Phentermine

• The website Drugs.com says that Phentermine is a drug that works like an amphetamine that may help decrease appetite. Because of its affordability over Meridia and Xenical, Phentermine is the most commonly prescribed drug for weight loss, comprising about 50 percent of all weight-loss prescriptions, according to Phentermine.com. Approved in 1959, the drug is sold under the brand names, Adipex-P and lonamin, as well as the generic phentermine, all of which require a prescription. Phentermine is the "phen" half of the banned drug "phen-fen."

  Serious side effects associated with Phentermine include chest pain, fainting, difficulty breathing and swelling of the lower extremities. More common side effects include depression, irritability and drowsiness.

Orlistat

• The over-the-counter weight-loss aid Alli is a lower-dose version of the generic drug Orlistat. The National Institutes of Health say that Orlistat is a lipase inhibitor, which works in the intestines by preventing the absorption of some of the fat in foods. This unabsorbed fat is then eliminated through the stool. Orlistat is also sold by the brand name Xenical and requires a prescription. Alli does not require a prescription.

  A warning by the Food and Drug Administration (FDA) was recently issued to users of Orlistat about possible damage to or failure of the liver. Other less serious side effects include oily spotting of the underwear, gas with oily spotting, diarrhea or loose stools, stomach pain and headache.