Xenical (Orlistat)

What is Xenical?

Xenical contains orlistat 120 mg in a hard capsule. It is a prescription medicine authorised in the EU for weight management alongside a mildly reduced-calorie diet. It acts in the digestive tract rather than as a central appetite suppressant.

Alli contains a lower dose of orlistat, 60 mg. It has separate instructions and supply conditions; this article concerns Xenical 120 mg. Product authorisation does not establish present stock.

How does it work?

Orlistat inhibits gastric and pancreatic lipases, enzymes that break down dietary fat. Some fat remains undigested and leaves the body in stools, reducing the calories absorbed from fat.

Systemic absorption is minimal, not zero. This does not mean there are no important interactions or kidney and liver risks. Digestive adverse effects should not be presented as a beneficial punishment or a guarantee of diet adherence.

Who is it for?

The EU indication is for patients with BMI ≥30 kg/m², or BMI >28 kg/m² with associated risk factors, alongside a mildly reduced-calorie diet. These criteria require an individual assessment; they do not guarantee prescribing.

Treatment must be discontinued after 12 weeks if weight loss is below 5% of starting body weight. Continued treatment depends on response and clinical review, not an automatic entitlement to a long course. Trials studied treatment for up to 4 years; that is not an individual duration recommendation.

Chronic malabsorption, cholestasis, breastfeeding and allergy to orlistat or an excipient are contraindications. Pregnancy requires caution under the EU label and clinical assessment; it must not be conflated with the breastfeeding contraindication. There is no relevant paediatric indication in the EU label, and this article provides an adult regimen.

Dosage and meals

Follow a balanced, mildly reduced-calorie diet with approximately 30% of calories from fat. Spread fat, carbohydrate and protein across three main meals. A high-fat meal increases digestive adverse effects.

A multivitamin containing vitamins A, D, E, K and beta-carotene may be considered. If recommended, take it at least 2 hours after orlistat or at bedtime, not before as an interchangeable timing rule.

Side effects

Very common digestive effects

Abdominal pain or discomfort, oily spotting, wind with discharge, faecal urgency, fatty or oily stools, flatulence, liquid stools, oily evacuation and increased bowel movements are very common (at least 1 in 10).

Common digestive effects

Rectal pain or discomfort, soft stools and faecal incontinence are common (at least 1 in 100 but fewer than 1 in 10). These are not the same category as the very common effects above. High dietary fat can worsen symptoms. Persistent or severe rectal bleeding needs medical investigation.

Serious reported effects

Hepatitis, which can be severe, and oxalate nephropathy, which can lead to kidney failure, have been reported after marketing; their frequency is unknown. Seek prompt medical care for jaundice, dark urine, persistent abdominal pain, reduced urination or other concerning symptoms. Kidney risk increases with chronic kidney disease or dehydration.

Seek emergency help for breathing difficulty or swelling of the face or throat. Severe abdominal pain may also require urgent assessment for pancreatitis or gallbladder disease. The list is not exhaustive and does not assign one frequency to all serious events.

Other products

There is no universally safest or best option. The mechanism of orlistat does not establish freedom from cardiovascular, psychiatric or interaction risks.

Important safety information

Do not take Xenical with chronic malabsorption, cholestasis, breastfeeding or allergy to an ingredient.

Tell the doctor about kidney disease, kidney stones, liver disease, pregnancy and diabetes. Weight loss may require clinician-led adjustment of diabetes treatment.

Interactions concern the combination, not instructions to stop another prescribed medicine yourself:

• Ciclosporin with orlistat is not recommended. If unavoidable, the prescriber must monitor ciclosporin levels more frequently when starting and stopping orlistat.
• Avoid concomitant acarbose because interaction studies are lacking.
• Warfarin and other oral anticoagulants require INR monitoring.
• Antiepileptic treatment may lose control; changes in seizure frequency or severity require assessment.
• HIV medicines and some psychiatric medicines may become less effective; the impact must be assessed before starting orlistat.
• Levothyroxine treatment and thyroid control need review; reduced absorption may contribute to hypothyroidism.
• Amiodarone may require closer clinical and ECG monitoring.
• Severe diarrhoea may reduce oral contraceptive reliability indirectly; use an additional contraceptive method in that situation.

Follow the complete leaflet and the clinical plan. Maintain nutrition and physical activity as advised.

Accessing an assessment

Prescrivia is a technology intermediary connecting patients with independent doctors. It does not prescribe medicines, employ doctors or sell medicines.

1. Provide weight, height, medical history, medication and previous weight-management attempts.
2. An independent doctor assesses suitability and may issue a prescription.
3. A licensed pharmacy assesses dispensing and delivery according to applicable rules and availability.

No prescription, supply or weight-loss result is guaranteed.

In Spain, distance sale of prescription medicines is prohibited under Article 3.5 of Royal Legislative Decree 1/2015. An online assessment does not remove this restriction. Dispensing and access depend on the exact product and applicable national rules.

Sources

• EMA: Xenical product information, sections 4.1–4.8 and 5.1–5.2.
• EMA: amfepramone withdrawal.
• EMA: Ozempic and Wegovy, product-specific indications.

This information does not replace individual medical advice or the complete leaflet.