Olistat120 mg

Olistat is a lipase inhibitor indicated for the management of obesity as follows:

Established / FDA-approved uses

• Weight loss and weight maintenance: Olistat is indicated for weight loss and weight maintenance when used together with a reduced-calorie, reduced-fat diet, in adults with an initial body mass index (BMI) of 30 kg/m² or greater, or 27 kg/m² or greater in the presence of other weight-related risk factors such as hypertension, type 2 diabetes, or dyslipidemia.
• Reduction of weight regain: Olistat is also indicated to reduce the risk of weight regain after prior weight loss.

Adjunct use — combination therapy required

• Olistat is only effective as an adjunct to a supervised, reduced-calorie, low-fat diet (approximately 30% of daily calories from fat, distributed over three main meals). It is not effective as monotherapy without dietary modification, and may be combined with a structured exercise programme for enhanced weight loss.

Pediatric/adolescent use

• Olistat 120 mg is approved for obesity management in adolescents aged 12 to 16 years, used together with a reduced-calorie, nutritionally balanced diet, under medical supervision.

Olistat does not treat the underlying cause of obesity; organic causes of obesity (e.g. hypothyroidism) should be excluded before starting therapy.

Each capsule contains Orlistat as the active pharmaceutical ingredient, available in strengths of 120 mg and 60 mg. Inactive ingredients typically include microcrystalline cellulose, sodium starch glycolate, povidone, sodium lauryl sulfate, and talc, with a gelatin capsule shell — exact excipients vary by manufacturer/brand.

Olistat is a reversible inhibitor of gastric and pancreatic lipase enzymes, used as an anti-obesity agent. Unlike centrally-acting appetite suppressants, Olistat acts locally within the gastrointestinal tract to reduce the absorption of dietary fat, and is not systemically absorbed to a clinically significant degree.

Olistat is available as an oral capsule in 120 mg (prescription strength) and 60 mg strengths, and is used as part of a comprehensive weight-management plan that includes a reduced-calorie, reduced-fat diet.

Olistat belongs to the therapeutic class of anti-obesity agents, and pharmacologically is classified as a gastrointestinal lipase inhibitor.

Mechanism of action

Orlistat acts by forming a covalent bond with the active serine residue site of gastric and pancreatic lipases, inactivating these enzymes. The inactivated enzymes are then unable to hydrolyze dietary fat (triglycerides) into absorbable free fatty acids and monoglycerides. Because the undigested triglycerides are not absorbed, the resulting caloric deficit contributes to weight loss.

Pharmacokinetics

• Absorption: Systemic absorption of Orlistat is minimal; it acts primarily within the lumen of the stomach and small intestine.
• Metabolism: The small amount absorbed is metabolized mainly within the gut wall.
• Excretion: The majority of the dose is eliminated unchanged in the feces.

Olistat is administered orally with water, taken during or up to one hour after a fat-containing meal. If a meal is skipped or contains no fat, that dose may be skipped. Do not exceed three doses (120 mg each) in 24 hours. Take a fat-soluble multivitamin at a separate time from Olistat, such as at bedtime.

The following clinically significant interactions have been established with Olistat:

• Fat-soluble vitamins/beta-carotene: Olistat reduces absorption of vitamins A, D, E, K and beta-carotene. Take a multivitamin supplement at least 2 hours before or after Olistat, preferably at bedtime.
• Cyclosporine: Olistat significantly reduces plasma cyclosporine levels (concentration and AUC decreased). Concomitant use is generally not recommended; if required, separate administration by at least 3 hours and monitor cyclosporine levels more frequently.
• Levothyroxine: Olistat may reduce levothyroxine absorption, and hypothyroidism has been reported with concurrent use. Separate dosing by at least 4 hours and monitor thyroid function.
• Warfarin and other oral anticoagulants: Olistat may reduce absorption of vitamin K, potentially altering INR. Monitor coagulation parameters closely if used concurrently.
• Antiepileptic drugs: Convulsions have been reported with concurrent use; monitor for changes in seizure frequency/control.
• Amiodarone: Olistat may reduce systemic exposure to amiodarone; clinical significance should be monitored.
• Antiretroviral drugs (e.g. atazanavir, ritonavir-boosted regimens): Loss of virologic control has been reported with concurrent use; avoid combination when possible, or monitor HIV RNA levels closely.

Adverse effects of Olistat are predominantly gastrointestinal, related to its mechanism of blocking fat absorption, and tend to occur more frequently with higher dietary fat intake. Counseling patients on adherence to a low-fat diet reduces the frequency of these effects.

Very common (gastrointestinal, fat-malabsorption related)

• Oily spotting/discharge from the rectum
• Flatulence with discharge
• Fecal urgency
• Oily or fatty stool
• Oily evacuation
• Increased frequency of defecation
• Fecal incontinence
• Abdominal pain/discomfort

Common

• Headache
• Upper respiratory tract infection
• Nausea

Rare but serious

• Severe liver injury, including hepatocellular necrosis and acute hepatic failure (some cases fatal or requiring transplant) — seek immediate medical attention for symptoms such as loss of appetite, jaundice, dark urine, or right upper abdominal pain.
• Oxalate nephrolithiasis and oxalate nephropathy with renal failure.
• Hypersensitivity reactions, including anaphylaxis and severe skin reactions.
• Cholelithiasis (gallstones), related to the degree of weight loss.
• Pancreatitis (postmarketing reports).

Pregnancy: Olistat is contraindicated during pregnancy, because weight loss offers no anticipated benefit during pregnancy and may cause fetal harm. Olistat should be discontinued if pregnancy occurs or is planned; use only if a physician determines it is clearly needed and potential benefit justifies potential risk — in general this drug should be avoided during pregnancy.

Lactation: It is not known whether Olistat passes into human breast milk. Caution should be exercised, and a physician should be consulted before use of Olistat in a nursing mother, weighing the benefits of breastfeeding against any theoretical risk.

• Fat-soluble vitamin deficiency: Olistat may reduce absorption of vitamins A, D, E, K and beta-carotene. A daily multivitamin should be taken, separated in time from Olistat (see Interactions).
• Dietary adherence: Olistat is effective only when combined with a reduced-calorie, low-fat diet; a high-fat diet increases the likelihood of gastrointestinal adverse effects (see Side Effects).
• Hepatic injury: Rare but serious liver injury has been reported (see Side Effects); advise patients to seek prompt medical attention for symptoms of liver injury, and discontinue Olistat if such symptoms occur.
• Renal effects: Increased urinary oxalate and cases of oxalate nephropathy with renal failure have been reported; use caution in patients with a history of hyperoxaluria, kidney stones, or renal impairment, and monitor renal function in at-risk patients.
• Malabsorption conditions: Not for use in patients with significant chronic malabsorption (see Contraindications).
• Cholelithiasis: Rapid or substantial weight loss can increase the risk of gallstones.
• Glycemic control: In diabetic patients, weight loss with Olistat may be associated with improved glycemic control; anti-diabetic medication doses may need adjustment under medical supervision.
• Exclude organic causes of obesity (e.g., hypothyroidism) prior to starting Olistat.

Studies of single doses up to 800 mg and repeated doses up to 400 mg three times daily have not shown significant adverse effects beyond the expected gastrointestinal effects of Olistat, and effects are expected to be reversible given its local, non-systemic mechanism of action. Nevertheless, in cases of suspected overdose, seek immediate medical attention or contact a poison control center/emergency services. Patients should be observed for at least 24 hours; management is supportive and symptomatic, since no specific antidote is known.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Pediatric use

Olistat 120 mg is approved for use in adolescents aged 12–16 years for obesity management, combined with a reduced-calorie diet and medical supervision. Safety and efficacy in children under 12 years have not been established, and use in this age group is not recommended.

Geriatric use

Clinical studies of Olistat did not include a sufficient number of subjects aged 65 years and over to determine whether they respond differently from younger patients. Use with appropriate caution, considering the greater frequency of comorbidities and concomitant medication in this population.

Renal impairment

No dedicated studies have been conducted in patients with renal impairment. Use with caution, and monitor renal function, particularly in patients at risk of oxalate nephropathy (see Precautions and Warnings).

Hepatic impairment

No dedicated studies have been conducted in patients with hepatic impairment. Because rare severe hepatic injury has been reported with Olistat, use with caution and monitor liver function in patients with pre-existing liver disease.

Olistat is generally used for weight management over an extended period as part of a comprehensive lifestyle programme. If a clinically meaningful amount of weight loss (e.g., approximately 5% of initial body weight) has not been achieved after about 12 weeks of therapy combined with diet and lifestyle changes, the prescriber should reassess treatment, since further benefit is unlikely without additional intervention. Long-term use should be periodically reviewed by the prescribing physician, weighing ongoing benefit against tolerability and the need for continued dietary adherence.

Orlistat is classified as an anti-obesity agent, specifically a pancreatic and gastric lipase inhibitor.

Orlistat works by covalently binding to and inhibiting gastric and pancreatic lipase enzymes within the gastrointestinal lumen. This prevents the breakdown of dietary triglycerides into absorbable fatty acids and monoglycerides, so roughly 25–30% of ingested fat passes through the gut unabsorbed and is excreted in the feces, producing a caloric deficit that supports weight loss when combined with dietary changes.

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Olistat 120 mg is indicated for the management of obesity in adolescents aged 12 to 16 years, used together with a nutritionally balanced, reduced-calorie diet, and under close medical and, where possible, family/dietary supervision. Adolescent patients should also take a daily multivitamin supplement containing fat-soluble vitamins, dosed apart from Olistat (see Interactions). Safety and efficacy of Olistat in children under 12 years of age have not been established, and use in this age group is not recommended.