Do prescription weight loss pills actually work

Overweight and obese people all over the world have one wish in common: a magic weight loss pill that will help them slim down quickly. Manufacturers and distributors in the weight loss industry make absolute fortunes selling diet pills, and will continue to do so for as long as there are people battling lose weight and keep it off.

The sheer volume of weight loss pills and supplements available makes it impossible to discuss it as a single topic. Some of these weight loss supplements or diet pills work, others don’t. Some are dangerous to use, and yet others may be quite harmless. This article will discuss a few of the more popular weight loss pills only available by prescription.

The trust that we have in our doctors and medical systems is based in a basic belief: doctors are meant to heal us, so any drug prescribed by a doctor must be good for us. While the intentions are good, it is also true that most drugs only available on doctor’s prescription are almost invariably dangerous under certain conditions, which is exactly why it can only be used under medical supervision. If these drugs were totally harmless, they would have been available over the counter.

The question then arises: why would a doctor prescribe something for you that may damage your health? Doctors have to weigh up the potential side effects of weight loss pills against the health benefits of losing weight and then make a judgment call. He or she also has to take into account your track record in losing weight following more conventional methods. It is important for all of us to research any drugs prescribed to us, so we can make informed decisions in following medical advice.

Weight loss pills can interact with other medications so it is important that your doctor considers all other medications you are on when prescribing something new. Sometimes people get so desperate to lose weight that they do not volunteer information for fear that the doctor may not prescribe the drug. Make sure your doctor have your full medical history and is aware of any other medications you may be on, so he or she can manage the risk of serious side effects occurring.

The most commonly prescribed weight loss pills are the following: orlistat (Xenical and Alli), sibutramine (Meridia) and phentermine (Adipex and Ionamin); all of which are FDA approved. Rimonabant (also sold as Acomplia, Monaslim and Slimona) is available in some countries. In November 2007, the British Medical Journal (BMJ) looked at the benefits and of prescription drugs for weight loss with specific focus on the weight loss results and side effects for orlistat, sibutramine and rimonabant. This study found that after using the drugs for 1 to 4 years, participants lost 6 pounds on average with orlistat, 9 pounds on average with sibutramine and 10 pounds on average with rimonabant. Other studies have found an average weight loss of 2 to 13 pounds with phentermine.


The following side-effects have been reported for these weight loss pills:

  • Orlistat. This drug only works on the digestive track, and acts as a fat blocker in that it reduces the absorption of fat by the body. Side effects reported include oily stools, grease spots on underwear, as well as uncomfortable urges to have a bowel movement. These side effects are normally only experienced when users do not follow a low fat diet. Concerns have been raised that the use of Orlistat may also decrease the absorption of vital vitamins and other nutrients from food, but no conclusive studies have been completed in this regard.
  • Sibutramine, an appetite suppressant, works by manipulating the levels of certain neurotransmitters (or chemical messengers) in the brain. While most people tolerate the drug quite well, the use of sibutramine may increase blood pressure and pulse rate. All patients treated with sibutramine should be regularly monitored for changes in blood pressure and pulse. Frequently reported side effects also include insomnia, nausea, dry mouth, upset stomach, headaches or constipation. Other side effects reported to occur on rare occasions include seizures, cardiac arrhythmia, mood changes, fever and jaundice.
  • Phentermine, like sibutramine, is also an appetite suppressant that works by stimulating the secretion of specific chemical messengers in the brain. In the past, Phentermine was used together with the drug fenfluramine. This combination was known as Fen-Phen. In some cases, the use of this weight loss drug led to heart valve damage or abnormal artery pressures in the lungs. Nowadays Fenfluramine is off the market. Phentermine on its own is still available in most countries, including the US. Most people can use Phentermine (on its own) without experiencing major side effects, but it may in some cases cause high blood pressure, rapid heartbeat, palpitations, restlessness, anxiety and insomnia. There are also some indications that the use of this drug can result in physical and psychological independence.
  • Rimonabant used to be prescribed as an appetite suppressant. The FDA has issued a recommendation against the use of Rimonabant for obesity in the United States and in October 2008 the European Medicines Agency also recommended that this drug not be prescribed due to the high risk of serious psychiatric problems and suicide. The drug was subsequently suspended. Theories have also been put forward that Rimonabant can promote the development of neuro-degenerative diseases of the nervous system such as Alzheimer’s disease, multiple sclerosis and Parkinson’s disease.

Just to summarize then. As old fashioned as it sounds, controlled daily calorie intake and regular exercise are still the cornerstones of weight control, but weight loss drugs certainly can be a part of treatment for a person who is severely overweight. Orlistat, Sibutramine and Phentermine are FDA approved, and should be safe to use, provided you stick to the doses and instructions prescribed. Rimonabant should be avoided as weight loss pill. It is important to remember that while diet pills drugs may help you lose weight faster, it is still up to you to change to a healthier lifestyle if you want to lose the weight for good.

The products discussed above are marketed under the following names:

Orlistat: Xenical, Alli (smaller dose available over the counter without prescription)

Sibutramine: Meridia, Ectiva, Reductil

Phentermine: Adipex P, Anoxine-AM, Ioamin, Duromin, Fastin, Obephen, Obermine, Obestin-30, Phentermene, Phentrol, Phenterex, Phentromin, Pro-Fast SA, Redusa, Panbesy, Phentermine Trenker, Obenix, Oby-Trim, Teramine, Zantryl, Sinpet, Supremin, Umine, Weltmine
Rimonabant (To be avoided): Accomplia, Bethin, Monaslim, Remonabent, Riobant, Slimona, Zimulti, Riomont

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1 Responses to “Do prescription weight loss pills actually work”


  • Thank you fro this article. It is a nice summary of what is available and certainly helped me understand the available options a lot better. I think I will now be able to have an informed discussion with my doctor on the best option for me. I am one of those people that need every little bit of help I can get to lose weight. I am over 40, and have been obese for more than 10 years now. It is not getting better, but worse. Hopefully my doctor will provide me with a prescription for one of these. Certainly from my perspective, Orlistat looks the safest. I am nervous about anything that messes with neurotransmitters.

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