Drugs for weight loss are only useful in certain cases and always as a supplement to diet and exercise
Last June, the media announced the existence of a drug that can cause weight loss of more than 20% in overweight patients. Dubbed tirzepatid, it has sparked public interest in this type of compound.
But the use of drugs to control obesity is not new. Although the basis of any treatment is a low-calorie diet combined with physical exercise, molecules that help shed excess pounds have also been around for decades.
Three proven effective compounds
There are currently three drugs available in Spain that have proven their effectiveness:
– Orlistat: It is an orally administered molecule that decreases the intestinal absorption of fat from food. You can lose up to 4% of your starting weight.
– Naltrexone: This opioid antagonist, used to treat alcoholism and prevent opiate use from recurring, is combined with bupropion, an antidepressant against smoking. The combined effect of both reduces appetite and achieves losses of 5% of body weight on average.
– Liraglutide: Daily subcutaneous administration, mimics the action of GLP-1 (glucagon-like peptide-1). This intestinal peptide, synthesized in response to the presence of food in the digestive tract, stimulates insulin secretion by the pancreas after meals. Another peptide is involved in the process, GIP (glucose-dependent insulinotropic polypeptides). GLP-1 and GIP also produce feelings of satiety by acting on a region of the brain called the hypothalamus. Patients who are prescribed lose up to 7% in weight.
soon in pharmacies
In addition, other drugs from this last group, known as incretin-mimetics-incretins, are expected to be included in the coming months. An example is semaglutide, which is given weekly subcutaneously and has shown weight reduction of up to 14%.
The molecule tirzepatide, which has recently attracted attention, has a dual effect: it acts simultaneously on the brain receptors for the incretins GLP-1 and GIP and regulates appetite. It is expected that in the medium term it will also be available in Spain, as well as other molecules currently in development.
It must be borne in mind that drugs used to treat obesity are not harmless. While orlistat can cause gas and fecal incontinence, naltrexone/bupropion occasionally causes nausea, constipation, headache, and insomnia and should not be given to individuals with certain psychiatric conditions.
For their part, the incretins (liraglutide, semaglutide, and tirzepatide) vary in their effectiveness: in some people they show remarkable effects, in others they are completely ineffective. In addition, they cause nausea and vomiting and are contraindicated in people with diseases of the pancreas.
When should they be used?
Although they can be of great help, medication is still an adjunct in the treatment of obesity. Physical activity is particularly relevant, since both medication and diet also decrease body water and muscle mass. Muscles can only be maintained and weight reduction achieved primarily through exercise at the expense of fat.
It must be emphasized that the treatment of obesity must be carried out under medical supervision. Among other things, the body mass index (BMI) is taken into account, which is calculated by dividing the body weight (in kilos) by the square of the height (in meters). The use of medication may be appropriate if the BMI is equal to or greater than 30 kg/m² or if it is greater than or equal to 27 kg/m² and the person has diabetes, hypertension or hypercholesterolemia.
At the moment we don’t have any drugs that have shown losses of more than 20% of body weight. In cases where superior descents must be achieved, gastrointestinal surgery is a therapeutic option. It is indicated when the BMI is equal to or greater than 40 kg/m², or for a BMI equal to or greater than 35 kg/m² if the patient has diabetes, hypertension or hypercholesterolemia.
When asked if there is a treatment to lose weight without making lifestyle changes, the answer is no. Drugs and surgery can be a good complement to diet and physical activity in certain cases of obesity, but they alone do not solve this pathology.
This article was published in ‘The conversation‘.