While Phentermine and Meridia were both popular in the US as well as the rest of the world, Meridia, also called Sibutramine, is no longer being produced for consumption in the United States. However, both drugs were (are) used to treat extreme cases of obesity but Phentermine is the only one still available on the United States market.

How Does Phentermine Work?

Phentermine acts as an appetite suppressant, or an anorectic drug, as well as a sympathomimetic drug, which works by releases certain chemicals in order to provide the results promised. Phentermine and its benefits are surrounded by the Fight or Flight reaction, which a person, or mammal of any kind will succumb to in times of high anxiety, fear and or stress. This drug starts by releasing noradrenaline, adrenaline and other catecholamines, all of which activate the Fight or Flight reaction.

What is the Fight or Flight Reaction and How Does it Help for Weight Loss?

When a person is in a high stress mode, often associated with anger and fear, the body will go into a mode of protection: Fight or Flight. This allows the person, or mammal, to react quickly to the situation, remain alert and it even inhibits ‘super’ strength and speed, which is normally unreachable under typical circumstances. This reaction will allow the person to literally not feel hungry because of the chemicals running through their body which enable the body to numb the hunger pangs associated with having an empty stomach. The hormones released will also increase your metabolism by many times, which will certainly help you to lose more weight than ever before as well as faster than ever.

What are the Dangers Associated with Phentermine?

There are many risk factors that are involved with the using of Phentermine. Increased energy may sound like a wonderful thing but with that comes the risk of heart attack, stroke and other serious cardiac related problems. Blood pressure and heart rate are both highly affected by the using of this medication, which is why it is available by prescription only.

While it may be frustrating, you will have to have frequent visits to your prescribing doctor when taking this drug because they will not only have to monitor your weight loss but they will have to check your heart rate and blood pressure constantly to make sure everything is as it should be.

Insomnia, irritability, mood swings and respiratory issues are also quite serious at times and often experienced when taking Phentermine. Again, your doctor should be able to monitor such symptoms and help you to deal with them properly. Most risks will come to those who aren’t healthy enough to begin with as well as to those who are abusing the drug or just not taking it properly.

How Does Meridia Work to Help Me Lose Weight?

Meridia, also known as Sibutramine, is an appetite suppressant that is both powerful and dangerous, which accounts for why a clinical study performed in the United States caused the products of the drug to come to a halt. The drug suppresses reuptake dopamine, norepinephrine and serotonin in order to deplete the feeling of the need for food.

Why is Meridia No Longer Available in the United States?

The manufacturers of Meridia (Sibutramine) halted their production of the drug based on a clinical study that was performed by field experts. The medication caused one of the highest risks to cardiac, respiratory and central nervous systems since the banning of Phen-Fen and other similarly banned weight loss drugs.

At a Glance – Phentermine VS Meridia


Phentermine, when considering that it is still highly used and being produced constantly, wins the battle by a landslide when compared to Meridia. While they both have their risks, Phentermine is still recommended by medical professionals everywhere to help fight obesity as long as it is taken on a short term basis and monitored by a doctor at all times. Each medication can be abused, which will increase the health risks significantly but for the most part Phentermine is a much better choice as long as you follow the precise prescription directions and never take matters into your own hands.