Intrathecal Baclofen refers to the delivery of the anti-hypertonia drug Baclofen directly into the spinal fluid space of the spine.  The rational for this is to obtain a higher amount of the drug at its treatment target site within the spinal cord while avoiding high drug concentrations in the brain and upper spinal cord where it can cause undesired side effects such as lethargy and respiratory depression.  To accomplish this an implanted drug reservoir with a pump is used to deliver a small amount of the drug via a thin catheter unto the spinal fluid space in the upper, mid- or lower back.   Typically, the concentration of the drug is 100 times higher at the point where the drug exits the catheter than it is in the brain when it is delivered in this manner.  This allows for a much high drug concentration to work at the target sites within the spinal cord without the worry of undesired side effects.  The concentration achieved is much higher than can be accomplished when the same medication is taken by mouth.

The neurosurgeon implanting the pumps for this treatment at Function was part of the initial FDA trial in the mid 1990s for the use of intrathecal baclofen to manage hypertonia in children.