Capsules d'Orlistat
Alli, Orlos, Xenical
Revu par Sid DajaniDernière mise à jour par Michael Stewart, MRPharmSLast updated 13 Oct 2023
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Take one capsule three times daily with your main meals.
If there is no fat in one of your meals, or if you miss a meal, there is no need for you to take a dose of orlistat.
Common side-effects include wind, loose stools and back passage (rectal) spotting, particularly at the beginning of treatment. These effects can be reduced by eating less fat in your meals.
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About orlistat
Type de médicament | An anti-obesity medicine |
Utilisé pour | The treatment of obesity alongside a reduced-calorie diet |
Aussi appelé | Xenical®; Alli®; Orlos® |
Disponible sous forme de | Capsules |
Orlistat is a medicine that can help you to lose weight if you are obese or overweight. It works by interfering with the way fat is digested and absorbed by your body. It prevents the action of enzymes found in the digestive juices of your stomach and small intestine. These enzymes normally break down the fat which you consume in your diet, allowing it to be absorbed into your bloodstream. By blocking the enzymes' action, orlistat reduces the digestion of fat. This allows the fat you have eaten to be passed out of your body instead of being absorbed by your body, and this helps you to lose weight.
Orlistat only prevents about a third of the fat you eat from being absorbed so it is also important for you to eat a lower-fat weight-reducing diet, and to exercise regularly.
Orlistat is available on prescription, and lower-strength capsules (Alli® brand) can also be bought from pharmacies. It is not suitable for everyone and a number of guidelines apply as to who can be supplied with orlistat - more information about this can be found in the separate health information leaflet called Orlistat Weight Loss Medicine.
Before taking orlistat
Retour au sommaireSome medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking orlistat it is important that your doctor or pharmacist knows:
Si vous êtes enceinte, essayez d'avoir un bébé ou allaitez.
Si vous avez des problèmes avec le fonctionnement de vos reins.
If you have a condition called chronic malabsorption syndrome, where your food is not absorbed properly.
If you have a problem with the flow of bile to your liver, a condition called cholestasis.
Si vous avez déjà eu une réaction allergique à un médicament.
Si vous prenez d'autres médicaments. Cela inclut tous les médicaments que vous prenez et qui sont disponibles à l'achat sans ordonnance, ainsi que les médicaments à base de plantes et les médecines complémentaires.
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How to take orlistat
Retour au sommaireBefore you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about orlistat and will provide you with a full list of the side-effects which you may experience from taking it.
Take orlistat exactly as your doctor or pharmacist tells you to. There are two strengths of capsules - 60 mg and 120 mg. The lower-strength capsule is available from pharmacies whilst the higher-strength capsule is only available on a prescription from a doctor.
The usual dose of orlistat is one capsule (60 mg or 120 mg) taken with each of your three main meals of the day. Swallow the capsule with a drink of water as you are about to eat the meal or soon afterwards. It can be taken up to one hour after a meal. Do not take more than three doses a day.
Orlistat only works when there are fats in what you eat, so if you miss a meal or if you eat a meal which is fat-free then do not take a dose of orlistat.
If you forget to take a dose, do not worry; just take a capsule with your next meal as usual. Do not take two doses together to make up for a forgotten dose.
Tirer le meilleur parti de votre traitement
Retour au sommaireOrlistat is only suitable if your body mass index (BMI) is 28 kg/m2 or greater. BMI is calculated by dividing your weight in kilograms by the square of your height in metres. So, for example, if you weigh 85 kg and are 1.7 metres tall, your BMI is 85/(1.7 x 1.7), which is 29. Alternatively, your practice nurse can measure and weigh you, and tell you your BMI.
To lose weight, the best chance of long-term success is to eat a well-balanced, calorie-controlled diet that is low in fat and rich in fruit and vegetables. If you are able, you should also exercise regularly. See the separate health information leaflet called Perte de poids (Réduction de poids) for more details. Your practice nurse will be able to give you further help and advice about eating a healthy diet and taking suitable exercise.
If you have bought orlistat from a pharmacy, check your weight regularly and, if you have not lost weight after three months, see your doctor or pharmacist for further advice. You must lose at least 5% of your weight within three months from starting orlistat; if not, the treatment should be stopped. Do not continue taking orlistat for longer than six months without seeing a doctor.
If you have been prescribed orlistat, your doctor will want to review your weight and treatment regularly to decide if it is still appropriate for you to carry on taking orlistat. You must lose at least 5% of your weight within three months from starting orlistat; if not, the treatment is likely to be stopped. It may also be necessary for you to have some blood tests during treatment to check your blood lipids. If you continue to lose weight after six months, your doctor may advise that you continue to take orlistat for up to a year, or possibly longer.
The fat which remains undigested from your diet can cause changes in your bowel habit, resulting in wind, loose stools, and oily spotting from your back passage. Reducing the amount of fat you eat in your meals will reduce the likelihood of these harmless, but unpleasant, side-effects.
Orlistat can interfere with the absorption of various medicines, including possibly the contraceptive pill. If you take 'the pill' and you have severe diarrhoea as a side-effect of taking orlistat, it could reduce the effectiveness of the contraception. If you experience diarrhoea, use another method of contraception in addition to the pill - for example, a condom.
Orlistat can also interfere with the absorption of vitamins which are fat-soluble. These are vitamins A, D, E and K. If you decide to take a multivitamin supplement, take it at a time when you are not also taking orlistat. The best time to take the supplement would be at bedtime.
If you have diabetes, it is important that you speak with a doctor before you start taking orlistat, as it can affect the control of your diabetes. This may require extra monitoring.
After you stop taking orlistat, you may put some weight back on. Remembering to continue with your healthy eating and increased level of physical activity can help to prevent this.
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Can orlistat cause problems?
Retour au sommaireAlong with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with orlistat. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
Very common orlistat side-effects (these affect more than 1 in 10 people) | Que puis-je faire si je ressens cela ? |
Lower tummy (abdominal) discomfort, oily spotting from your back passage, wind, loose oily stools, an urgent need to open your bowels, pain around your back passage | These symptoms generally occur at the start of treatment as your body is adjusting. Reducing the fat content in your meals will help |
Maux de tête | Buvez beaucoup d'eau et demandez à un pharmacien de vous recommander un antidouleur approprié. Si les maux de tête persistent, informez votre médecin |
Throat and chest infections, flu-like symptoms | If troublesome, speak with your doctor or pharmacist for advice |
Important: if you experience any bleeding from your back passage, speak with your doctor for advice.
Si vous ressentez d'autres symptômes que vous pensez être dus aux capsules, consultez votre médecin ou votre pharmacien pour obtenir des conseils supplémentaires.
How to store orlistat
Retour au sommaireGardez tous les médicaments hors de la portée et de la vue des enfants.
Conserver dans un endroit frais et sec, à l'abri de la chaleur et de la lumière directes.
Informations importantes sur tous les médicaments
Retour au sommaireInformations importantes sur tous les médicaments
Si vous achetez des médicaments, vérifiez avec un pharmacien qu'ils sont sans danger à prendre avec vos autres médicaments.
Ne prenez jamais plus que la dose prescrite. Si vous soupçonnez que vous ou quelqu'un d'autre avez pris une surdose de ce médicament, rendez-vous au service des urgences de votre hôpital local. Emportez le contenant avec vous, même s'il est vide.
Si vous subissez une opération ou un traitement dentaire, informez la personne qui effectue le traitement des médicaments que vous prenez.
Ce médicament est pour vous. Ne le donnez jamais à d'autres personnes, même si leur état semble être le même que le vôtre.
Ne gardez pas de médicaments périmés ou indésirables. Apportez-les à votre pharmacie locale qui s'en débarrassera pour vous.
Si vous avez des questions concernant ce médicament, demandez à votre pharmacien.
Signaler les effets secondaires d'un médicament ou d'un vaccin
Si vous ressentez des effets secondaires, vous pouvez les signaler en ligne via le Yellow Card website.

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Vérifiez les interactions possibles entre les médicaments, les compléments et les aliments avant de les prendre ensemble.
Lectures complémentaires et références
- Manufacturer's PIL, Xenical® 120 mg hard capsules; Neon Healthcare Ltd, The electronic Medicines Compendium. Dated January 2022.
- Manufacturer's PIL, Alli® 60 mg hard capsules; Haleon UK Trading Limited, The electronic Medicines Compendium. Updated February 2023.
- Médicaments Complets BNF 89e Édition; Association Médicale Britannique et Société Royale Pharmaceutique de Grande-Bretagne, Londres.
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Historique de l'article
Les informations sur cette page sont rédigées et examinées par des cliniciens qualifiés.
Next review due: 12 Oct 2026
13 Oct 2023 | Dernière version

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