II. Indication: Obesity Management

  1. Body Mass Index over 30 kg/m2
  2. Body Mass Index over 27 kg/m2 with comorbidity
    1. Diabetes Mellitus
    2. Hypertension
    3. Dyslipidemia

III. Mechanism

  1. Pentanoic acid ester binds gastric, pancreatic Lipase
  2. Lipase Inhibitor (Blocks Fat absorption)
    1. Decreased Triglyceride absorption
    2. Decreased Cholesterol absorption

IV. Pharmacokinetics

  1. Minimal systemic absorption

V. Efficacy

  1. Weight loss is greater with 120 mg (7.5 lb or 3.4 kg) than with 60 mg (5.5 lb or 2.5 kg)
  2. Combined results of two large Placebo controlled trials
    1. Year one
      1. Orlistat: 9-10 kg loss (10% of baseline weight)
      2. Placebo: 6 kg (6% of baseline weight)
    2. Year two
      1. Orlistat: 1.5-3 kg regained weight
      2. Placebo: 4-6 kg regained weight
  3. References
    1. Sjostrom (1998) Lancet 352:167 [PubMed]
    2. Davidson (1999) JAMA 281:235 [PubMed]

VI. Adverse effects

  1. Gastrointestinal side effects (40%)
    1. Flatus with discharge
    2. Oily stool with spotting
    3. Fecal urgency
    4. Fecal Incontinence
    5. Abdominal Pain
  2. Fat soluble Carotenoid (fruit, vegetable) malabsorption
  3. Fat soluble Vitamin malabsorption (daily MVI recommended in package insert)
    1. Vitamin A
    2. Vitamin D
    3. Vitamin E
    4. Vitamin K

VII. Drug Interactions

  1. Does not interfere with absorption of other medications
    1. Coumadin
    2. Oral Contraceptives
    3. Antihypertensives

VIII. Dosing

  1. Take three times daily with each meal containing fat
  2. Prescription dose: 120 mg orally three times daily
  3. OTC dose: 60 mg orally three time daily

IX. Precautions

  1. Avoid fat-soluble Vitamins within 2 hours of Orlistat
  2. Maintain Dietary Fat intake <30% of calories

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Cost: Medications

orlistat (on 12/20/2023 at Medicaid.Gov Survey of pharmacy drug pricing)
ORLISTAT 120 MG CAPSULE Generic $6.99 each
xenical (on 9/16/2022 at Medicaid.Gov Survey of pharmacy drug pricing)
XENICAL 120 MG CAPSULE $8.03 each