Weight Loss Pills - Phenteramine - Sibutramine - Orlistat - Rimonabant

Some Weight Loss Drugs

Orlistat and phenteramine are used as anti-obesity medicines. Lorcaserin and phenteramine/ topiramate have been recently approved for the purpose. Others like sibutramine and rimonabant have been banned in most countries.

The anti-obesity drugs include:

Orlistat

Orlistat (Xenical or Alli) reduces intestinal fat absorption by inhibiting pancreatic lipase. Xenical is moderately effective, leading to an average weight loss of 12 to 13 pounds over a year. Most of this weight loss is experienced within the first 6 months.

Side effects of orlistat include

• Oily spotting bowel movements (steatorrhea)
• Oily stools
• Stomach pain
• Flatulence
• Inability to control bowel movements
• Increased number of bowel movements

These side-effects can be reduced by decreasing the fat intake.

Mutivitamin supplementation is essential while taking orlistat as it inhibits the absorption of certain vitamins. The vitamins should be taken two hours before or after taking orlistat.

Lorcaserin

Lorcaserin is the first FDA-approved diet pill since 1999. It may be used for chronic weight management in adult patients, including those with a weight-related condition like high blood pressure, high cholesterol level or type 2 diabetes.

Common side effects observed in clinical trials are:

• Headache
• Upper respiratory tract infection, nasopharyngitis, sinusitis
• Nausea, diarrhea, constipation
• Sometimes, depression, anxiety, suicidal ideation

Phentermine

Phenteramine is an appetite suppressant used for the short-term treatment of weight loss along with diet, exercise and other lifestyle modifications. Its use has been associated with some serious side effects. These include:

• Primary pulmonary hypertension
• Valvular heart disease
• Altered level of alertness
• Withdrawal effects following prolonged use
• Impotence

Phenteramine plus topiramate

The combination of phenteramine plus topiramate has been approved by the FDA just after lorcaserin for the treatment of obesity. Topiramate is otherwise used to treat seizures. The combination can increase heart rate and therefore should be used with caution in people with recent unstable heart disease or stroke.

Sibutramine

Sibutramine (Reductil or Meridia) reduces the desire to eat.

Side-effects of sibutramine include:

• Increase blood pressure
• Dry mouth
• Constipation
• Headache
• Insomnia

Sibutramine has been withdrawn from most countries including the United States, UK, the EU, Australia and India as its risks of myocardial infarction and stroke outweigh its benefits.

Rimonabant

Rimonabant (Acomplia) is cannabinoid (CB1) receptor antagonist that acts centrally on the brain thus decreasing appetite. It may also act peripherally by increasing thermogenesis and thereby increasing energy expenditure.

The drug has not received FDA approval in the US and Canada due to safety concerns, primarily psychiatric in nature. It has been withdrawn in most countries including India due to reports of depression and suicidal behavior as well as seizures.

Metformin

Metformin (Glucophage) limits the amount of glucose that is produced by the liver and increases muscle consumption of glucose. It reduces weight in people with diabetes mellitus type 2, and is sometimes used as a diet pill, though not FDA approved for this purpose.

Reference for Weight Loss Drugs

1. Coutinho W. The first decade of sibutramine and orlistat: a reappraisal of their expanding roles in the treatment of obesity and associated conditions. Arq Bras Endocrinol Metab. 2009;53/2: 262-70.
2. Tziomalos K, Krassas G, Tzotzas T. The use of sibutramine in the management of obesity and related disorders: An update. Vascular Health and Risk Management 2009:5 441�452
3. Leite C, Mocelin CA, Petersen GO, Leal MB, Thiesen FV. Rimonabant: an antagonist drug of the endocannabinoid system for the treatment of obesity. Pharmacological Reports 2009, 61:217-224
4. Questions and Answers about FDA�s Initiative Against Contaminated Weight Loss Products- (http://www.fda.gov/Drugs/ResourcesForYou/Consumers/QuestionsAnswers/ucm136187.htm)