Intrathecal baclofen: does tolerance occur?

Abstract

Concern over the development of tolerance in patients on continuous intrathecal baclofen therapy has arisen as this new form of treatment for spasticity has gained wider use. We have studied time-dose relationships in 18 spinal cord injured patients who have undergone intrathecal baclofen infusion pump implantation since February 1988 in our facility. Our data show that there was a significant increase in baclofen dosage needed to control spasticity during the first 12 months post implantation. After 12 months, however, no significant changes in dosage requirement was detected. In addition, there was no significant difference between completely and incompletely spinal cord injured patients with regard to both the initial dose and the tolerance trend.

Subdural catheter migration may lead to baclofen pump dysfunction

“…11 In cases of drug delivery failure patients present with a severe rebound of their spasticity, which can lead to rhabdomyolysis and consequently renal failure. Our patient had been already treated three times for a rhabdomyolysis since the implantation of his DAD 11 years ago.…”

Intrathecal baclofen in tetraplegia of spinal origin: efficacy for upper extremity hypertonia

“…Other investigators have also described a linear relationship. 33 It is our belief that this relationship is secondary to dosage adjustments to optimize e cacy following pump placement along with increasing drug tolerance. Prior studies with intrathecal baclofen have also noted increasing dosage requirements with the passage of time.…”

“…1,5,8,33 This has been attributed to the downregulation of GABA-B receptors at the spinal level. 1,33 In our study, the slight increase in tone at 12 months is also suggestive of emerging tolerance. Akman found a signi®cant increase in dosage requirements up until 12 months followed by a leveling o from 12 to 24 months.…”

“…Akman found a signi®cant increase in dosage requirements up until 12 months followed by a leveling o from 12 to 24 months. 33 Others have also suggested a plateauing e ect. 10,11,13 When progressive tolerance has become an issue, it has been successfully treated with`drug holidays'.…”

“…33 In order to clarify this issue and its clinical implications, additional long-term (412 months) studies are needed. This should become a reality as the numbers of patients increase and we continue to gain experience with the use of intrathecal baclofen.…”