Orlistat xenical is a lipase inhibitor for obesity management that acts by inhibiting the absorption of dietary fats.Orlistat Xenical is (S)-2-formylamino-4-methyl-pentanoic acid (S)-1-[[(2S, 3S)-3-hexyl-4-oxo-2-oxetanyl] methyl]-dodecyl ester. Its empirical formula is C29H53NO5, and its molecular weight is 495.7. It is a single diastereomeric molecule that contains four chiral centers, with a negative optical rotation in ethanol at 529 nm.
Orlistat is a white to off-white crystalline powder. Orlistat is practically insoluble in water, freely soluble in chloroform, and very soluble in methanol and ethanol. Orlistat has no pKa within the physiological pH range.

XENICAL orlistat is available for oral administration in dark-blue, hard-gelatin capsules, with light-blue imprinting. Each capsule contains 120 mg of the active ingredient, orlistat. The capsules also contain the inactive ingredients microcrystalline cellulose, sodium starch glycolate, sodium lauryl sulfate, povidone, and talc. Each capsule shell contains gelatin, titanium dioxide, and FD&C Blue No.1, with printing of pharmaceutical glaze NF, titanium dioxide, and FD&C Blue No.1 aluminum lake.

Orlistat (Xenical®)
Approved indication: Management of obesity in patients with a body mass index (BMI) > 30 kg/m2 or a BMI > 27 kg/m2 in the presence of other cardiovascular risk factors (e.g. hypertension, diabetes, etc.).Mechanism of action: Reversibly inhibits gastric and pancreatic lipases, decreasing the absorption of dietary fat (triglycerides) by about 30%.Pharmacokinetics: About 2% of orlistat is absorbed and this is mostly metabolized within the gastrointestinal wall. Most of the drug is excreted unchanged in the feces.

Evidence of effectiveness: Four double-blind RCTs are available to assess effectiveness.1-4 Three of these measured weight loss over a 1-year period in 1901 obese patients with and without Type 2 diabetes (BMI > 28 kg/ m2) eating a mildly hypocaloric diet.1-3 Pooled data from these 3 trials reveal that weight averaged 100 kg at baseline and 26.4% of patients withdrew during the first year. In patients completing one year of the trial, the mean decrease in weight with orlistat 120 mg tid was 8.9 kg vs 5.6 kg with placebo. The fourth trial studied the effect of orlistat on weight maintenance over a 1-year period.4 Obese subjects who had lost >8% of their initial body weight on a hypocaloric diet over a 6 month period were randomised to placebo or orlistat. During one-year follow-up, weight gain with orlistat 120 mg tid was 2.6 kg, significantly less than with placebo, 4.4 kg.Major adverse effects: Oily spotting, 27%, flatus with discharge, 24%, increased defecation, 11%, and fecal incontinence, 8%, occurred more commonly with orlistat than with placebo. More patients taking orlistat (14%) required vitamin A and D supplementation than patients taking placebo (6.5%).Dose and cost: Available in 120 mg capsules. Recommended dose: 1 capsule tid with meals (maximum duration 2 yrs). Daily cost: $4.38.

Conclusion: In obese patients orlistat in combination with a low-fat diet (<30% of calories) reduces body weight by 3.3 kg in the first year as compared to placebo

XENICAL (orlistat) is a lipase inhibitor for obesity management that acts by inhibiting the absorption of dietary fats.Orlistat XENICAL is indicated for obesity management including weight loss and weight maintenance when used in conjunction with a reduced-calorie diet. XENICAL is also indicated to reduce the risk for weight regain after prior weight loss. XENICAL is indicated for obese patients with an initial body mass index (BMI) >/=30 kg/m2 or >/=27 kg/m2 in the presence of other risk factors (eg, hypertension, diabetes, dyslipidemia).