Xenical

About Xenical

Xenical is the original branded form of orlistat, developed and manufactured by Roche. It was the first prescription weight loss medicine of its kind licensed in the UK and remains one of the most extensively studied, with over two decades of clinical use behind it.

Each capsule contains 120mg of orlistat, identical in strength and effect to generic orlistat. Some people simply prefer the branded product, and Xenical remains a popular choice for that reason.

Expected weight loss

In the four-year XENDOS study, participants taking Xenical alongside lifestyle changes lost an average of 5.8kg compared with 3.0kg on placebo. The study also found a 37% reduction in progression to type 2 diabetes among participants with impaired glucose tolerance.

Who is Xenical for?

Xenical may be prescribed for adults with a BMI of 30 or above, or 28 or above with a weight-related risk factor. It is a good option if you want a well-established, non-hormonal treatment, or if GLP-1 medicines are unsuitable for you.

The commitment it asks for

Xenical works with a low-fat diet, not around one. The treatment and the diet are a package, one does not function well without the other.

How Xenical works

Xenical contains orlistat, a lipase inhibitor. It acts entirely within your digestive tract and is barely absorbed into the bloodstream at all.

The mechanism

Fat in food arrives as triglycerides, which are too large to pass through the gut wall. Lipase enzymes break them into absorbable fragments. Orlistat binds to gastric and pancreatic lipase and switches it off, so around 30% of the fat in your meal is never broken down and simply passes through.

What this means in calories

Fat provides 9 calories per gram, more than twice that of protein or carbohydrate. Blocking a third of the fat in a typical day's eating removes several hundred calories without any change to portion sizes. Combine that with a genuinely reduced-fat diet and the deficit compounds.

What it does not do

Xenical has no effect on appetite, hunger or cravings. It does not affect the absorption of carbohydrate or protein, and it will not offset calories from sugar or alcohol. It is a targeted tool, not a general one.

How to take Xenical

When

One 120mg capsule with each of your three main meals. Take it immediately before, during, or within one hour of eating.

When to skip a dose

Skip the capsule if you miss a meal or if the meal contains no fat. There is nothing for the medicine to act on, and taking it unnecessarily only raises the chance of side effects.

The diet that makes it work

• Keep fat to no more than about 30% of your daily calories
• Distribute fat evenly across your three meals, around 20g each at 1,800 calories a day
• Include plenty of fruit and vegetables
• Watch for hidden fat in sauces, pastry, cheese, processed meat and fried food

Vitamin supplementation

Take a daily multivitamin containing A, D, E and K at bedtime, at least two hours after your final capsule of the day.

Missed dose

If more than an hour has passed since your meal, skip that dose. Resume with your next meal. Never take two capsules at once.

Side effects

Xenical's side effects are gastrointestinal and directly linked to how much fat you eat.

Very common (more than 1 in 10 people)

• Oily or fatty stools
• Urgency to open your bowels
• Wind, sometimes with oily discharge
• Abdominal pain or discomfort
• More frequent bowel movements

Common (up to 1 in 10 people)

• Bowel incontinence
• Bloating and soft stools
• Tooth or gum problems
• Headache, tiredness and anxiety
• Irregular periods
• Upper respiratory infections

Seek medical advice

• Severe or ongoing abdominal pain
• Jaundice, dark urine, itching or unusual fatigue, possible liver problems
• Blood in your stools
• Signs of an allergic reaction such as rash or swelling

Side effects are most pronounced early on and usually ease as your diet adapts. If they are severe, the answer is nearly always less fat rather than a lower dose.

Ingredients

Active ingredient: orlistat 120mg per capsule.

Other ingredients: microcrystalline cellulose, sodium starch glycolate, povidone, sodium laurilsulfate and talc. The capsule shell contains gelatin, indigo carmine (E132), titanium dioxide (E171) and edible printing ink.

Manufactured by Roche. Supplied in packs of 84 (28 days), 168 (56 days) or 252 (84 days) at three capsules daily.

Important safety information

Do not take Xenical if you:

• Are pregnant or breastfeeding
• Have chronic malabsorption syndrome
• Have cholestasis
• Are allergic to orlistat or any other ingredient

Discuss with your prescriber if you have kidney disease or a history of kidney stones, type 2 diabetes, thyroid disease, or a history of eating disorders.

Medicine interactions: Xenical can reduce absorption of ciclosporin, levothyroxine, amiodarone, antiepileptics and certain HIV medicines, and can affect warfarin control. Separate levothyroxine and ciclosporin doses by at least four hours.

Contraception: if you experience severe diarrhoea, use additional contraception, as absorption of oral contraceptives may be reduced.

Always read the patient information leaflet supplied with your medicine.