Orlistat Chemical formula
Synonyms: Orlipastat; Orlistaatti; Orlistatum; Ro-18-0647; Ro-18-0647/002; Tetrahydrolipstatin. N-Formylhexyl-4-[(2S)-2-hydroxytridecyl]-2-oxetanone; (S)-1-[(2S,3S)-3Hexyl-4-oxo-oxetan-2-ylmethyl]dodecyl N-formyl
Cyrillic synonym: Орлистат.

💊 Chemical information

Chemical formula: C29H53NO5 = 495.7.
CAS — 96829-58-2.
ATC — A0 8AB01.
ATC Vet — QA08AB01.

💊 Adverse Effects

Gastrointestinal disturbances, including faecal urgency and incontinence, flatulence, and fatty stools or discharge, are the most frequently reported adverse effects during treatment with orlistat. They may be minimised by limiting the amount of fat in the diet. Other reported effects have included headache, anxiety, fatigue, and menstrual irregularities. There have been concerns about an increased risk of breast cancer in patients taking orlistat but the manufacturers consider that there is no evidence of a causal link.

Effects on the cardiovascular system.

A report of hypertension associated with orlistat therapy.1 Blood pressure decreased on stopping orlistat and increased again on rechallenge. The authors noted that 13 cases of hypertension associated with orlistat had been reported to the manufacturers.
1. Persson M, et al. Orlistat associated with hypertension. BMJ 2000; 321: 87.

Effects on the skin.

Lichenoid drug eruption affecting the vulva, feet, and axillae has been reported in a woman during orlistat treatment.1 Symptoms resolved on stopping orlistat with only the vulval lesions requiring topical treatment with mometasone furoate 0.1%.
1. Sergeant A, et al. Lichenoid eruption associated with orlistat. Br J Dermatol 2006; 154: 1020–21.

💊 Precautions

Orlistat should not be given to patients with chronic malabsorption syndrome or cholestasis and should be given with caution to patients with a history of hyperoxaluria or calcium oxalate nephrolithiasis. Adjustments to dosage of hypoglycaemics may be necessary in patients with type II diabetes because of improved metabolic control after weight loss in these patients. Supplements of fat-soluble vitamins may be necessary during long-term therapy, but they should be taken at least 2 hours before or after an orlistat dose or at bedtime. Hormonal contraceptive failure may occur in the event of severe diarrhoea with orlistat, and patients are advised to use an additional contraceptive method.

💊 Interactions

Orlistat may reduce the absorption of fat-soluble vitamins. Licensed product information recommends that it not be taken with acarbose. In patients taking warfarin, international normalised ratio should be monitored during treatment with orlistat. A reduction in ciclosporin concentrations to subtherapeutic levels has been reported in transplant recipients given orlistat. Orlistat may also reduce the absorption of propafenone. For the possibility of hormonal contraceptive failure with orlistat see Precautions, above.

💊 Pharmacokinetics

Orlistat is minimally absorbed after oral doses.

💊 Uses and Administration

Orlistat is a gastric and pancreatic lipase inhibitor that limits the absorption of dietary fat. It is used together with dietary modification in the management of obesity, i.e. in patients with a BMI of 30 kg/m2 or greater. It may also be used in overweight patients with a BMI of 27 kg/m2 or more if there are associated risk factors. Orlistat is given in a usual dose of 120 mg orally three times daily, immediately before, during, or up to 1 hour after meals. If a meal is missed or contains no fat, the dose should be omitted. Orlistat therapy should be stopped if the patient does not lose at least 5% of their body-weight during the first 12 weeks of therapy.
1. NICE. Guidance on the use of orlistat for the treatment of obesity in adults (issued March 2001). Available at: http://www.nice.org.uk/ nicemedia/pdf/orlistatguidance.pdf (accessed 06/08/08
2. Lucas KH, Kaplan-Machlis B. Orlistat—a novel weight loss therapy. Ann Pharmacother 2001; 35: 314–28
3. Keating GM, Jarvis B. Orlistat: in the prevention and treatment of type 2 diabetes mellitus. Drugs 2001; 61: 2107–21
4. Snider LJ, Malone M. Orlistat use in type 2 diabetes. Ann Pharmacother 2002; 36: 1210–18
5. Torgerson JS, et al. XENical in the prevention of diabetes in obese subjects (XENDOS) study: a randomized study of orlistat as an adjunct to lifestyle changes for the prevention of type 2 diabetes in obese patients. Diabetes Care 2004; 27: 155–61
6. Guy-Grand B, et al. Effects of orlistat on obesity-related diseases—a six-month randomized trial. Diabetes Obes Metab 2004; 6: 375–83
7. Chanoine J-P, et al. Effect of orlistat on weight and body composition in obese adolescents: a randomized controlled trial. JAMA 2005; 293: 2873–83. Correction. ibid.; 294: 1491
8. Henness S, Perry CM. Orlistat: a review of its use in the management of obesity. Drugs 2006; 66: 1625–56
9. Filippatos TD, et al. Orlistat-associated adverse effects and drug interactions: a critical review. Drug Safety 2008; 31: 53–65.

💊 Preparations

Proprietary Preparations

Arg.: Crisplus; Fingras; Xenical; Xeniplus; Xinplex; Austral.: Xenical; Austria: Xenical; Belg.: Xenical; Braz.: Xenical; Canad.: Xenical; Chile: Viplena; Xenical; Cz.: Xenical; Denm.: Xenical; Fin.: Xenical; Fr.: Xenical; Ger.: Xenical; Gr.: Xenical; Hong Kong: Xenical; Hung.: Xenical; Indon.: Xenical; Irl.: Xenical; Israel: Xenical; Ital.: Xenical; Malaysia: Xenical; Mex.: Redustat; Xenical; Neth.: Xenical; Norw.: Xenical; NZ: Xenical; Philipp.: Xenical; Pol.: Xenical; Port.: Xenical; S.Afr.: Xenical; Singapore: Xenical; Spain: Xenical; Swed.: Xenical; Switz.: Xenical; Thai.: Xenical; Turk.: Xenical; UK: Xenical; USA: Alli; Xenical; Venez.: Xenical.
Published May 08, 2019.