Low-dose baclofen therapy raised plasma insulin-like growth factor-1 concentrations, but not into the normal range in a predictable and sustained manner in men with chronic spinal cord injury.
OBJECTIVE
To evaluate, whether once-daily oral baclofen administration increases and/or sustains plasma insulin-like growth factor-1 (IGF-1) concentration in 11 men with chronic spinal cord injury (SCI) and IGF-1 deficiency (i.e. <250 ng/ml).


METHODS
Prospective, open-label, dose titration study. Baclofen was administered at 20 mg/day for 8 weeks; then increased to 40 mg/day for another 8 weeks. Plasma IGF-1 and self-reported side effects were measured at baseline and every other week for the duration of the study.


RESULTS
The subjects were 43 ± 12 years old, had duration of injury of 20 ± 12 years; eight subjects had a complete motor injury, and eight had paraplegia. Nine of 11 subjects completed the 20 mg/day treatment and 5 subjects completed the 40 mg/day treatment. Plasma IGF-1 levels improved with each baclofen dose; however, only one subject increased from baseline and remained above the targeted physiological range of 250 ng/ml throughout treatment. A significant increase in IGF-1concentration was observed between baseline and week 2 (154 ± 63 vs. 217 ± 69 ng/ml; P < 0.05), weeks 8 and 10 (188 ± 95 vs. 228 ± 93 ng/ml; P < 0.05), and weeks 8 and 16 (188 ± 95 vs. 259 ± 92 ng/ml; P < 0.05). No serious side effects were observed at 20 mg/day; the 40 mg/day dose was less well tolerated.


CONCLUSIONS
Baclofen was not effective at sustaining plasma IGF-1 concentrations in the physiological range in men with chronic SCI.
James J. Peters VA Medical Center, Bronx, NY, USA. william.bauman@va.gov
William A
WA
Bauman
Michael F
MF
La Fountaine
Christopher M
CM
Cirnigliaro
Steven C
SC
Kirshblum
Ann M
AM
Spungen
D000328:Adult; D001418:Baclofen / Q000008:administration & dosage* / Q000009:adverse effects; D002908:Chronic Disease; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000172:deficiency* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009125:Muscle Relaxants, Central / Q000008:administration & dosage / Q000009:adverse effects; D009128:Muscle Spasticity / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D010264:Paraplegia / Q000097:blood / Q000150:complications; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011782:Quadriplegia / Q000097:blood / Q000150:complications; D012016:Reference Values; D013119:Spinal Cord Injuries / Q000097:blood / Q000150:complications*; D013739:Testosterone / Q000097:blood
D009125:Muscle Relaxants, Central; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D001418:Baclofen