A combination of 6 months of treatment with pyridostigmine and triweekly exercise fails to improve insulin-like growth factor-I levels in fibromyalgia, despite improvement in the acute growth hormone response to exercise

J Rheumatol. 2007 May;34(5):1103-11. Epub 2007 Apr 1.


Objective: People with fibromyalgia (FM) often have low insulin-like growth factor-I (IGF-I) levels and a suboptimal growth hormone (GH) response to acute exercise. As previous work had demonstrated a normalization of the acute GH response to exercise with the use of pyridostigmine (PYD), we tested the hypothesis that 6 months of PYD therapy plus supervised exercise would increase IGF-I levels.

Methods: Subjects with primary FM were randomized into 4 groups: (1) PYD/exercise; (2) PYD/diet recall; (3) placebo/exercise; and (4) placebo/diet recall. The dosing of PYD was 60 mg tid for 6 months. Resting IGF-I levels were measured at baseline and after 6 months of treatment. In addition the acute GH response to exercise at VO2 max was measured at baseline and after treatment.

Results: A total of 165 FM subjects (mean age 49.5 yrs, 5 male) were entered and 154 (93.3%) completed the study. Six months of therapy (PYD plus exercise or exercise alone) failed to improve the IGF-I levels. The use of PYD 1 hour prior to exercise improved the acute GH response (4.54 ng/dl) compared to placebo (1.74 ng/dl) (p = 0.001) at the end of the 6-month trial. The acute GH response to exercise at baseline did not correlate with IGF-I, age, depression, medications, estrogen status, or obesity.

Conclusion: A combination of triweekly supervised exercise plus the daily use of PYD for 6 months failed to increase IGF-I levels in patients with FM, despite the confirmation that PYD normalizes the acute GH response to strenuous aerobic exercise.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Cholinesterase Inhibitors / therapeutic use*
  • Combined Modality Therapy
  • Double-Blind Method
  • Exercise Therapy*
  • Female
  • Fibromyalgia / blood
  • Fibromyalgia / physiopathology
  • Fibromyalgia / rehabilitation*
  • Growth Hormone / blood*
  • Humans
  • Insulin-Like Growth Factor I / metabolism*
  • Male
  • Middle Aged
  • Pyridostigmine Bromide / therapeutic use*
  • Treatment Failure
  • Treatment Outcome


  • Cholinesterase Inhibitors
  • Insulin-Like Growth Factor I
  • Growth Hormone
  • Pyridostigmine Bromide