Orlistat

Absorption: Studies on normal-weight and obese volunteers have shown that the body absorbs very little orlistat, and the intact orlistat plasma concentration cannot be measured 8 hours after oral administration (5ng/mL). The systemic absorption of the usual therapeutic dose of orlistat is extremely limited, with no accumulation. Only occasionally can intact orlistat be detected in plasma at very low concentrations (10ng/mL or 0.02μm). Distribution: Since orlistat is almost not absorbed, it is difficult to determine its distribution volume, and systemic pharmacokinetics cannot be detected. In vitro, more than 99% of orlistat is bound to plasma proteins (lipoproteins and albumin are the main binding proteins). Orlistat rarely binds to red blood cells. Metabolism: Animal experiments suggest that the metabolism of orlistat is mainly concentrated in the gastrointestinal wall. Studies conducted in obese patients have shown that among the very small portion of the drug components absorbed systemically, there are two major metabolites, M1 (4-ring lactone ring hydrolysis product) and M3 (M1 attached to an N-formyl leucine cleavage product), accounting for 42% of the total plasma concentration. M1 and M3 have an open b-lactone ring with very weak lipase inhibitory activity (1000-fold and 2500-fold lower than orlistat, respectively). At therapeutic doses, the inhibitory activity and plasma concentrations of M1 and M3 are very low (average M1-26μg/mL and M3-108μg/mL), so these two metabolites have no pharmacological significance. Elimination: Studies on normal weight and obese subjects have shown that unabsorbed drugs are mainly excreted through feces. About 97% of the dose taken is excreted in the feces, of which 83% is unchanged orlistat, and the cumulative renal excretion of all orlistat-related substances is less than 2%. It takes 3 to 5 days for the drug to be completely excreted (feces and urine). The metabolism of orlistat is very similar for normal weight and obese subjects. Orlistat, M1 and M3 can all be excreted through bile. Determination of the fat content in feces showed that the efficacy of this drug can be seen 24-48 hours after administration, and the fat content in feces will return to the pre-treatment level 48-72 hours after stopping treatment.

The main active ingredient of this product is orlistat. Excipients include: microcrystalline cellulose, sodium starch glycolate, polyvinyl pyrrolidone, sodium lauryl sulfate and talc. The capsule shell contains gelatin, sodium indigo disulfonate (E132), and titanium dioxide.

White needle crystals or powder.

For the treatment of obese or overweight patients (BMI ≥ 24).

Adults: The recommended dose is one 120 mg capsule taken with or within one hour after a meal. If a meal is missed or the food does not contain fat, one dose can be omitted. The therapeutic effects of long-term use of Xenical (including weight control and improvement of risk factors) can be sustained. The patient's diet should be nutritionally balanced, low in calories, with about 30% of the calories coming from fat, and the food should be rich in fruits and vegetables. The intake of fat, carbohydrates and protein should be distributed over three meals a day. There is no evidence that more than three times a day/120 mg each time can enhance the efficacy. No dosage adjustment is required for the elderly.

It mainly causes gastrointestinal adverse reactions, which are related to the pharmacological effect of the drug in preventing the absorption of ingested fat. Common adverse reactions are: oily spots, increased gastrointestinal flatulence, urgency to defecate, fatty (oily) stools, steatorrhea, increased frequency of bowel movements and fecal incontinence. The acute gastrointestinal reactions that usually occur more frequently in patients taking Xenical are: abdominal pain/abdominal discomfort, flatulence, watery stools, soft stools, rectal pain/rectal discomfort, dental discomfort, and gum discomfort. Other rare adverse events observed are: upper respiratory tract infection, lower respiratory tract infection, influenza, headache, menstrual disorders, anxiety, fatigue, and urinary tract infection. There are occasional reports of allergies to this product. The main clinical manifestations are itching, rash, urticaria, angioedema and allergic reactions.

It is contraindicated in patients with chronic malabsorption syndrome, cholestasis, or hypersensitivity to orlistat or any of the ingredients in the drug preparation.

In pharmacokinetic studies, no drug interactions were observed between orlistat and alcohol, digoxin, metformin, nifedipine, oral contraceptives, phenytoin, pravastatin, or warfarin. Reduced absorption of vitamins D, E, and beta-carotene has been observed when taken with Xenical. If a multivitamin supplement is needed, it should be taken at least 2 hours after Xenical. Alternatively, it should be taken at bedtime. Decreased plasma concentrations of cyclosporine A have been observed when taken concurrently with Xenical. Therefore, increased monitoring of cyclosporine A plasma concentrations should be performed when Xenical and cyclosporine A are co-administered (see PRECAUTIONS).

Keep sealed.