Together with sibutramine *, orlistat is one of the most widely used drugs in the treatment of obesity. Since this pathology, given the impressive amount of risk factors associated with it, is far from being a simple aesthetic problem, the use of drugs such as orlistat (also known as tetra-hydro-lipostatin) represents an important achievement of pharmaceutical research.
Trade names: Xenical ® - Alli ® orlistat
Orlistat-based drugs:
- ALLI ® - Orlistat
- XENICAL ® - Orlistat
Action mechanism
Leaving the road of dangerous amphetamines and their derivatives, unfortunately still unconsciously undertaken by some people or worse still by unscrupulous doctors, the researchers' attention turned to the search for alternative drugs. In the case of orlistat, the idea was to produce a drug capable of reducing the absorption of dietary fats, which are 98% triglycerides. This effect was achieved through the development of an active ingredient capable of inhibiting gastrointestinal lipases, ie those enzymes responsible for the splitting of triglycerides into simpler and easily absorbed fragments from the intestinal mucosa (fatty acids plus monoglycerides).
Thanks to the orlistat, the triglycerides passed undamaged to the digestive attack of lipases, cannot be absorbed by the intestinal mucosa and are therefore eliminated with the faeces. In fact, this drug has a chemical structure very similar to that of triglycerides. Consequently, the high affinity with the intestinal and pancreatic lipases, causes the orlistat to bind to them in a stable way, significantly reducing the enzymatic share available to the digestion of triglycerides.
Effectiveness, side effects and precautions for use
Studies lasting more than two years on the therapeutic efficacy of the orlistat, have shown that at therapeutic doses, its intake leads to a weight loss, compared to the initial weight, of 10%, against a 5% reduction in the group of patients treated with the same low-calorie and placebo diet therapy. In the second year of treatment, subjects who switched from placebo to orlistat experienced weight loss, while there was a reversal of the trend, with weight regain, in the group switched from orlistat to placebo.
At therapeutic doses (120 mg three times a day, at main meals), orlistat is able to reduce the absorption of dietary fat by 30%; higher dosages do not seem to favor further weight loss.
There are also positive effects on the reduction of total cholesterol and LDL (or "bad"), while the share of essential fatty acids and fat-soluble vitamins absorbed in the intestine decreases (multivitamin supplementation may be necessary before going to bed).
The most important problem, which is the basis of the side effects of orlistat, lies in the fate of the triglycerides that escaped the digestive process which, metabolized by the resident bacterial flora, cause the classic disorders associated with steatorrhea. This condition, which indicates the presence in the faeces of a lipid quota higher than the norm, is accompanied by flatulence, incontinence, oily excrements and fecal urgency (vaseline oil, for example, is a classic emollient laxative). These effects are directly proportional to the lipid quota introduced into the meal and therefore represent an important educational tool. Fearing to run into these disorders, the patient tends to acquire a greater awareness of the amount of fat he introduces with the diet, learning to prefer leaner food sources.
Orlistat is contraindicated in subjects with chronic malabsorption, with cholestasis, during pregnancy and during lactation. Particular caution in the simultaneous association with hypoglycemic drugs, as orlistat interferes with oral antidiabetic therapy (type II diabetes is widespread among obese subjects). The concomitant administration of orlistat is also not recommended with the following drugs: fibrates, acarbose, biguanides and anorectics.
Treatment with orlistat should be discontinued if, within 12 weeks of its introduction, there is no weight loss equal to or greater than 5% of the weight recorded at the beginning of the therapy. Given its mechanism of action, orlistat is not recommended when following low-calorie and highly hypolipid food patterns.
A natural "drug" against obesity, lacking the side effects of orlistat and other medicines intended for its treatment, is fiber. Swelling at the gastric level, requiring a slower mastication and therefore increasing the sense of satiety, promoting the excretion with fat and bile acid feces and positively modulating the absorption of sugars, the fiber contained in vegetables and whole grains represents the milestone of obesity diet therapy. It is effective, it is cheap and represents only one of the innumerable benefits that can be obtained by following a diet rich in fruits, vegetables and foods rich in fiber.
Fiber supplements, and psyllium in particular, may also be associated with orlistat therapy to control the side effects associated with steatorrhea.
