Weight Loss Drugs

There are many products promising the weight loss, but the majority of them are just dietary supplements with uncertain effectiveness. There are only few real dietary drugs. However, they may have significant side effects, they should be used only when prescribed by a doctor and their prescription is significantly reduced or even banned in certain countries.


The majority of weight loss drugs can be distinguished into two main groups.

Drugs acting on the nervous system

These preparations reduce feeling of hunger and they are technically referred to as anorectics. Typical representatives are substances sibutramine and phentermine. Phentermine has some adverse effects on the psyche and it should not be used in certain diseases such as pulmonary hypertension and in glaucoma. Sibutramine has much more frequent severe side effects and increased incidence of ischemic strokes and heart attacks was reported in its users. Therefore, sibutramine preparations are in any countries withdrawn from the legal sale.

Drugs affecting the absorption of nutrients

Orlistat is a typical substance if this group. It prevents the absorption of fats in the intestine and this shall lead to weight reduction. However, even these drugs have many side effects, typically on digestive system. When the patient eats a diet with a high amount of fats, the drugs cause occurrence of yellowish, oily and smelling diarrhea.


Weight loss drugs do not represent a large percentage of prescribed preparations.  However, when properly indicated, the may be important in reduction of obesity. Of course, when the patient wants to reduce weight, usage of any drugs must be accompanied with healthy lifestyle and dietary measures. Given the potentially serious side effects, the drugs should be always prescribed by a doctor.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources