Health Centres - Xenical
How does it work?
Xenical capsules contain the active ingredient orlistat, which is a type of medicine called a lipase inhibitor. It is used to aid weight loss in people who are obese.
Orlistat is not absorbed into the bloodstream, but works locally in the stomach and small intestine, where it prevents the action of two compounds found in the digestive juices. These compounds (known as enzymes) are called gastric and pancreatic lipases. They normally break down fats that we consume in our diet.
The fats we consume in our diets are made of molecules that are too large to be absorbed from the gut into the bloodstream. They need to be broken down into smaller molecules during the process of digestion, in order to be absorbed into the bloodstream. Gastric and pancreatic lipases are the compounds in the gut that carry out this function.
Orlistat works by preventing gastric and pancreatic lipases from working. It is taken at mealtimes to prevent fat that is eaten in the meals from being broken down and absorbed by the body. This means the body cannot use the fat as a source of energy, or convert it into fat tissue. Instead, the fat is excreted in the faeces. This helps weight loss.
Orlistat is prescribed to aid weight loss in obese people who have a body mass index (BMI) of 30kg/m² or more. It can also be prescribed to overweight people who have a BMI of 28kg/m² or more, if they also have additional risk factors for obesity-related diseases.
Orlistat should be used in conjunction with a mildly low calorie diet. Ask your doctor, pharmacist or dietician for advice on what to eat while taking orlistat. Your doctor may ask you to stop treatment if you have been unable to lose at least five per cent of your body weight after 12 weeks of treatment.
What is it used for?
-
Obesity
Warning!
- This medicine should be taken immediately before, during, or up to one hour after each main meal. If a meal is missed, or contains no fat, you should leave out the dose. This is because the medicine will have no effect if no fat has been consumed.
- This medicine may potentially impair the absorption of fat-soluble vitamins (A,D,E,K) from the gut. To ensure you receive adequate nutrition, your diet should be rich in fruit and vegetables. Your doctor may also recommend a multivitamin supplement. If you do take a multivitamin supplement, it should be taken at least 2 hours after your orlistat dose, or at bedtime.
- If you experience severe or persistant rectal bleeding while taking this medicine you should consult your doctor so that this can be investigated.
- This medicine can cause diarrhoea, which if severe, can reduce the effectiveness of oral contraceptive pills. Women taking the pill for contraception should therefore use an additional method of contraception, eg condoms, to prevent pregnancy, if they experience severe diarrhoea while taking this medicine.
- This medicine has not been studied in children under 12 years of age, elderly people, or those with impaired liver or kidney function.
Use with caution in
-
Diabetes
Not to be used in
- Long term inability of the gut to absorb sufficient nutrients (chronic malabsorption syndrome)
-
Failure of the normal flow of bile from the liver to the intestines
-
Breastfeeding
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
Pregnancy and Breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- The safety of this medicine in pregnancy has not been established. It should therefore be used with caution during pregnancy, and only if the benefits to the mother outweigh any possible risks to the foetus. Seek medical advice from your doctor.
- The safety of this medicine during breastfeeding has not been established. For this reason, the manufacturer states that it should not be used during breastfeeding. Seek medical advice from your doctor.
Side effects
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Headache
- Oily spotting from the rectum
- Abdominal pain or discomfort
- Flatulence (wind) with discharge
- Oily or fatty stools
- Urgent or increased need to open the bowels
- Diarrhoea
- Pain or discomfort in the rectum
- Infections of the airways
- Low blood sugar levels (hypoglycaemia) in people with diabetes
- Faecal incontinence
- Fatigue
- Urinary tract infection
- Irregular menstrual cycle
- Anxiety
- Tooth or gum disorders
- Diverticulitis
- Gall stones
- Raised liver enzymes
- Inflammation of the liver (hepatitis)
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.
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