Anti-obesity drugs: Xenical and Alli

Anti-obesity drugs: Xenical and Alli

The old appetite suppressant drugs such as amphetamines and fenfluramine is not any more used because they had too many side effects. At present, only a molecule received the marketing authorization for anti-obesity drugs: the orlistat which it is marketed under the trade name Xenical by Roche and is sold as Alli by GlaxoSmithKline.

Anti-obesity drugs

Mechanism of action

The orlistat belongs to the class of drugs called anti-obesity agents and more particularly to those of the gastrointestinal lipases inhibitors. Associated with a diet slightly reduced to calories, containing no more than 30 % of calorie intake in form of lipids, it is used to help the obese people to lose weight and to maintain their new weight.

The lipase is an enzyme necessary for the decomposition of fats contained in food and for their transformation to fatty acids, absorbed by the body. The orlistat blocks the action of the lipase and thus it prevents the absorption of fats. Taken in the recommended doses, the orlistat blocks the absorption about 30 % of fats contained in food.

This Drug should be used only by people whose body mass index (BMI) is equal or upper to 30 kg / m ², or by people whose BMI is equal or upper to 27 kg / m ² and who present other risk factors as a high blood pressure, a type 2 diabetes, a high rate of cholesterol or a big waist measurement.

It can be also used in association with antidiabetics drugs to improve the blood glucose control of obese or overweight people reached of type 2 diabetes whose the glycemia is not enough mastered by a diet, by a program of exercises and by  the antidiabetics as the glyburide, the insulin and the metformin.


  • Principle active: Orlistat
  • Excipients: The capsule contents: microcrystalline Cellulose (E460), carboxymethyl sodium starch, Povidone (E1201), Sodium lauryl sulfate (E487), Talc (E553b), The capsule tunic: gelatin, Indigotine (E132), Titanium dioxide (E171),Printing inks for food: Iron oxides (E172), Solution ammonium concentrated, Potassium hydroxide (E525), Lac (E904), Propylene glycol (E1520).

Posology and administration mode

The dose recommended for adult is 120 mg taken 3 times a day with the main meals of the day (breakfast, lunch and dinner) or till 1 hour after the meal. If, occasionally, a meal is jumped or if it does not contain fats, the dose of orlistat can be omitted. Swallow the whole capsule with water.

If a meal is jumped or it doesn’t contain fats, the taking of orlistat must be deleted.

You should take the orlistat in parallel with a balanced diet, slightly reduced to calories, containing no more than 30 % of the calorie intake in form of lipids, according to the recommendations of your doctor, dieteticien or another healthcare professional.

Several factors can be taken into account to determine the dose which a person needs: his weight, his health and his taking of the other drugs. If your doctor recommended a dose other than those indicated here, do not modify the way of taking the drug without consulting him beforehand.

Keep this drug in the ambient temperature in its original packaging, shielded from the heat and from the humidity and out of reach of children.


Abstain from using the orlistat in circumstances below:

  • An allergy for the orlistat or for one of the drug ingredients;
  • A cholestasis (a disorder characterized by the stop of the bile production by the liver);
  • A syndrome of chronicles malabsorption chronicles (an affection characterized by a bad absorption of the food nutrients).

Side effects

At least 1 % of people taking this drug indicated the side effects below. A large number of these side effects can be taken care and some can disappear from themselves in time:

  • An abdominal pain;
  • The anxiety;
  • Back pain;
  • Discolored saddles;
  • dizziness;
  • The dry skin;
  • The fatigue
  • Flatulence with faecal flow;
  • Headaches;
  • The incapacity to master the evacuation of faeces;
  • An increase of the faeces emission;
  • Menstrual irregularities;
  • Muscle pains;
  • Nausea;
  • Greasy or oily saddles;
  • Oily spots on underwear;
  • Rectal pain;
  • Soft or liquid saddles;
  • Dental disorders;
  • Infections of the superior respiratory tracts;
  • A need urgent to go to stool;
  • Vaginal irritation;
  • Vomiting.

Most of the side effects appearing below do not arise very often, but they could however engender grave problems if you do not consult your doctor or if you do not receive medical care:

  • A rectal bleeding;
  • A depressive state;
  • A sensation of dullness;
  • A skin rash;
  • A swelling of feet or of ankles;
  • Symptoms attributable to gallstones (as a pain in the right top of the belly which can be accompanied with nausea and with vomiting);
  • Symptoms attributable to kidney stones (as back pain and presence of blood in the urine);
  • Symptoms of liver disease (as an abdominal pain, a dark urine, a loss of appetite, the yellowing of the skin or the eyes).

Stop taking the drug and request immediately medical care if there is an answer as:

  • Signs of an allergic reaction such as a rash, a breathlessness or a respiratory difficulty, a swelling of eyes, mouth, lips or throat.

Interactions with other drugs

It could occur an interaction between the orlistat and one of the agents below:

  • The amiodarone (antiarrhythmic medication);
  • The beta-carotene;
  • The contraceptive pill;
  • Certain drugs against the diabetes (the glyburide, the gliclazide, the insulin, the metformin);
  • The cyclosporine (immunosuppressant drug);
  • The liposoluble vitamins (vitamin A, vitamin D, vitamin E and vitamin K);
  • The levothyroxine (treat low thyroid activity);
  • Oral anticoagulants (as the warfarin);
  • The antiepileptic drugs (or anticonvulsants such as the carbamazepine and the phenytoin).


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