The drug works by increasing the serotonin levels in the brain that makes the brain believe that the stomach is already full and thus, increases the person's metabolic rate.

It was only after scientists discovered that these drugs had side effects and were indicated to cause heart valve disease that these were taken off the shelves. Such drugs included fenfluramine and particularly its infamous cocktail with phentermine called Phen-Fen.

Later on, modifications have been made and new drugs were developed and prescribed by doctors and many of which are still waiting for FDA approval. One such drug approved by FDA is Xenical.

For obvious reasons the idea that a simple drug can change everything without the need to change ones diet or sacrificing anything is very tempting. And since people have seen friends and family members use it and have shown tremendous improvement, the idea sells. This has made a lot of people spend millions of dollars every year to also experience this miracle and has given drug companies a lot of money making these weight loss drug and selling it.

There are many factors that have contributed to the obesity being witnessed in U.S.A and around the world. They include the rise in the number of fast foods joints that contain a lot of saturated fat in the meals, the use of refined sugar in sodas and other processed foods, eating food with less fiber, genetics, overeating and as people age slow metabolism. Infact more and more studies keep showing that more people are getting overweight every year. This is not only happening to adults but even to kids who have just started in school.

Since losing weight takes time most people can't wait to get rid of it. And either due to lack of knowledge or inspite of it, many people have decided to take the fastest way out through the use of these weight loss drugs.

Diet pills can be purchased either over-the-counter as supplements or prescribed by a doctor as it is with weight loss drugs. But even with the advances in medical technology, these drugs and supplements still pose a health risk to the public. Problems in patients can be unpleasant such as diarrhea and vomiting, harmful such as tightness in the chest and in the urinary tract and fatal such as a heart attack or a stroke.

An overdose in using weight loss tablets can cause tremors, confusion, hallucinations, shallow breathing, renal failure, heart attack and convulsions.

The side effects vary depending on the lifestyle and health of the person and can be minimized as long as one consults the doctor and follows the prescribed dosage when using it.

And should one decide to stop using the drugs, studies have shown that a person will experience withdrawal symptoms and side effects. These include noticeable mood swings, hyper-activity, and pain in the stomach, insomnia and nightmares, severe irritability, extreme fatigue, depression, nausea, vomiting and trembling.

A lot of clinical tests will show that the taking some weight loss diets really work. But this can only work if it is done with a form of low calorie diet and an exercise plan.

A person can jog every morning or sign up and workout in a gym. Just like taking any medicine, one should first consult the doctor before undergoing any form of exercise. The best exercise plan should have cardiovascular and weight training exercises. This helps burn calories and increase the muscle to fat ratio that will increase ones metabolism and lose weight.

But does it not make you wonder that weight loss drugs need you to add diet and exercises to be effective? Probably the point to take home is that whether you choose t use a weight loss drug or not, diet and exercises are still pivotal in achieving weight loss.