Alli, Xenical
Classifications: anorectant; nonsystemic lipase inhibitor;
Therapeutic: nonsystemic lipase inhibitor

Prototype: Diethylpropion
Pregnancy Category: B


60 mg, 120 mg capsules


Nonsystemic inhibitor of gastrointestinal lipase. Reduces intestinal absorption of dietary fat by forming inactive enzymes with pancreatic and gastric lipase in the GI tract.

Therapeutic Effect

Indicated by weight loss/decreased body mass index (BMI). Reduces the intestinal absorption of dietary fat because at least 95% of orlistat is eliminated in the feces; reduces caloric intake in obese individuals.


Weight loss and weight maintenance in patients with BMI ≥30 kg/m2 or ≥27 kg/m2 in patients with other risk factors. Reduce risk for weight regain after prior weight loss.


Hypersensitivity to orlistat; malabsorption syndrome; cholestasis; gallbladder disease; hypothyroidism; organic causes of obesity; anorexia nervosa, bulimia nervosa; organic causes of obesity, lactation. Safety and efficacy in children <12 y are not established.

Cautious Use

Gastrointestinal diseases including frequent diarrhea; known dietary deficiencies in fat soluble vitamins (i.e., A, D, E); history of calcium oxalate nephrolithiasis or hyperoxaluria; older adults; pregnancy (category B).

Route & Dosage

Weight Loss
Adult/Adolescent (>16 y): PO 60–120 mg t.i.d. with each main meal containing fat


  • Give during or up to 1 h after a meal containing fat.
  • Omit dose with nonfat-containing meal or if meal is skipped.
  • Store at 15°–30° C (59°–86° F). Keep bottle tightly closed; do NOT use after the printed expiration date.

Adverse Effects (≥1%)

Body as a Whole: Fatigue. CNS: Headache, dizziness, anxiety. CV: Hypertension, stroke. GI: Oily spotting, flatus with discharge, fecal urgency, fatty/oily stool, oily evacuation, increased defecation, fecal incontinence, abdominal pain/discomfort, nausea, infectious diarrhea, rectal pain/discomfort, tooth disorder, gingival disorder, vomiting. Skin: Rash. Urogenital: Menstrual irregularity.

Diagnostic Test Interference

Monitor PT/INR in patients on chronic stable doses of warfarin.


Drug: Orlistat may increase absorption of pravastatin; may decrease absorption of fat soluble vitamins (A, D, E, K).


Absorption: Minimal. Metabolism: In gastrointestinal wall. Elimination: In feces. Half-Life: 1–2 h.

Nursing Implications

Assessment & Drug Effects

  • Monitor weight & BMI; closely monitor diabetics for hypoglycemia.
  • Coadministered drugs: Monitor PT/INR with warfarin.
  • Monitor BP frequently, especially with preexisting hypertension.

Patient & Family Education

  • Take a daily multivitamin containing fat-soluble vitamins at least 2 h before/after orlistat.
  • Remember common GI adverse effects typically resolve after 4 wk therapy.
  • Avoid high fat meals to minimize adverse GI effects. Distribute fat calories over three main meals daily.
  • Monitor weight several times weekly. Diabetics: Monitor blood glucose carefully following any weight loss.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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