Effects of orlistat on fat-soluble vitamins in obese adolescents

Pharmacotherapy. 2002 Jul;22(7):814-22. doi: 10.1592/phco.22.11.814.33627.


Study objectives: To determine whether orlistat causes fat-soluble vitamin deficiencies in African-American and Caucasian adolescents.

Design: Prospective, open-label pilot study.

Setting: Warren Grant Magnuson Clinical Center of the National Institutes of Health.

Patients: Seventeen adolescents with body mass indexes above the 95th percentile for age, race, and gender who also had at least one obesity-related comorbid condition.

Intervention: Subjects received orlistat 120 mg 3 times/day and a daily multivitamin supplement containing vitamin A 5000 IU, vitamin D 400 IU, vitamin E 300 IU, and vitamin K 25 microg.

Measurements and main results: During 3-6 months of orlistat treatment, acute absorption of retinol (vitamin A) was not significantly altered, but absorption of alpha-tocopherol (vitamin E) was significantly reduced compared with baseline levels (p<0.001). Serum levels of vitamins A and E did not change significantly; however, there was a nonsignificant decrease in vitamin K. Mean vitamin D levels were significantly reduced compared with baseline (p<0.02) after 1 month of orlistat, despite multivitamin supplementation.

Conclusion: It may be prudent to monitor vitamin D concentrations in adolescents who take orlistat, even when a multivitamin is prescribed.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Analysis of Variance
  • Avitaminosis / blood*
  • Avitaminosis / chemically induced
  • Child
  • Female
  • Humans
  • Lactones / adverse effects
  • Lactones / therapeutic use*
  • Male
  • Obesity / blood*
  • Obesity / drug therapy*
  • Orlistat
  • Pilot Projects
  • Prospective Studies
  • Vitamin A / blood
  • Vitamin D / blood
  • Vitamin E / blood


  • Lactones
  • Vitamin A
  • Vitamin D
  • Vitamin E
  • Orlistat