Dosing and uses of Alli, Xenical (orlistat)
Adult dosage forms and strengths
capsule
- 60mg (Alli)
- 120mg (Xenical)
Obesity Management
Indicated in patients with pretreatment BMI >30 kg/m², or BMI >27 kg/m² in presence of other risk factors or diseases (eg, HTN, DM, hyperlipidemia)
Rx (Xenical): 120 mg PO q8hr with each fat-containing meal (during or up to 1 hr after the meal), doses >120 mg TID show no additional benefit
OTC (Alli): Up to 60 mg PO q8hr with each fat containing meaL
Only effective as an adjunct to caloric restriction, increased physical activity, and behavioral modification
Also see Administration and Cautions (drug interaction overview)
Pediatric dosage forms and strengths
capsule
- 60mg
- 120mg
Obesity Management
Indicated in patients with pretreatment BMI >30 kg/m², or BMI >27 kg/m² in presence of other risk factors or diseases (eg, HTN, DM, hyperlipidemia)
<12 years: Safety and efficacy not established
≥12 years
- Rx (Xenical): 120 mg PO q8hr with each fat-containing meal (during or up to 1 hr after the meal), doses >120 mg TID show no additional benefit
- OTC (Alli): Up to 60 mg PO q8hr with each fat containing meal
- Only effective as an adjunct to caloric restriction, increased physical activity, and behavioral modification
- Also see Administration and Cautions (drug interaction overview)
Alli, Xenical (orlistat) adverse (side) effects
1-10%
Oily spotting (5%)
Frequency not defined
Flatulence
Fatty/oily stooL
Increased defecation
Fecal incontinence
Nausea
Vomiting
Reduced absorption of fat soluble vitamins and beta-carotene
Liver failure
Oxalate nephropathy
Leukocytoclastic vasculitis
Warnings
Contraindications
Pregnancy
Chronic malabsorption syndrome
Cholestasis
Hypersensitivity
Cautions
If a meal is missed or contains no fat, dose should be omitted
Daily fat intake (30% of calories), carbohydrate, and protein should be evenly distributed over 3 main meals
Note: Multivitamin supplement (including vit A, D, E, K) is recommended
Postmarketing reports of severe liver injury with hepatocellular necrosis or acute hepatic failure with some cases resulting in liver transplant or death
History of hyperoxaluria or calcium oxalate nephrolithiasis; cases of oxalate nephrolithiasis and oxalate nephropathy with renal failure have been reported
Substantial weight loss can increase risk of cholelithiasis
Exclude organic causes of obesisty (eg, hypothyroidism), before prescribing therapy
May increase gastrointestinal events when taking a diet high on fat (>30% total daily calories from fat)
Diabetes mellitus
Avoid with anorexia nervosa or bulimia
Drug interaction overview
- Cyclosporine: Administer cyclosporine 3 hr after orlistat
- Levothyroxine: Administer 4 hr apart; monitored for changes in thyroid function
- Amiodarone PO: A pharmacokinetic study showed reduced amiodarone and desethylamiodarone systemic exposure when coadministered with orlistat
- Antiepileptic drugs (AEDs): Convulsions reported with coadministration of AEDs and orlistat; monitor serum AED levels
- Antiretroviral drugs: Loss of virological control has been reported in HIV-infected patients taking orlistat concomitantly with antiretroviral drugs; HIV RNA levels should be frequently monitored in patients taking orlistat and antiretrovirals drugs; if HIV viral load increases, discontinue orlistat
- Warfarin
- Vitamin K absorption may be decreased with orlistat
- Reports of decreased prothrombin, increased INR, and unbalanced anticoagulant treatment resulting in change of hemostatic parameters have been with coadministration of orlistat and anticoagulants
- Patients on chronic stable doses of warfarin or other anticoagulants who are prescribed orlistat should be monitored closely for coagulation parameters changes
- Vitamin supplements
- Orlistat may reduce absorption of some fat-soluble vitamins and beta-carotene
- Instruct patient to take a multivitamin containing fat-soluble vitamins to ensure adequate nutrition
- Take vitamin supplement at least 2 hr before or after taking orlistat, such as at bedtime
Pregnancy and lactation
Pregnancy category: X; weight loss offers no potential benefit to a pregnant woman and may result in fetal harm; a minimum weight gain, and no weight loss, is currently recommended for all pregnant women, including those who are already overweight or obese
Lactation: Not recommended; not known if orlistat is distributed in breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Alli, Xenical (orlistat)
Mechanism of action
Inhibits gastric and pancreatic lipases, prevents triglyceride hydrolysis resulting in decreased absorption of dietary fats
Absorption
Bioavailability: 5%; absorption is very low and systemic absorption of orlistat is not required for clinical efficacy
Onset: 24-48 hr
Duration: 48-72 hr
Peak Plasma Time: 6-8 hr
Distribution
Protein Bound: 99%
Metabolism
Metabolized in intestinal walL
Metabolites: M1 & M3 (both probably inactive)
Elimination
Half-Life: 1-2 hr
Renal Clearance: 0.1% of dose/hr
Excretion: Feces 95-97% (including biliary); urine < 3%
Administration
Oral Administration
Take with each fat-containing meal (during or up to 1 hr after the meal)
The patient should be on a nutritionally balanced, reduced-calorie diet that contains ~30% of calories from fat
Daily intake of fat, carbohydrate, and protein should be distributed over 3 main meals
If a meal is occasionally missed or contains no fat, omit the orlistat dose
