What is the elimination half-life of baclofen in cerebrospinal fluid after a single intrathecal bolus injection or short-term infusion?

Baclofen’s cerebrospinal fluid elimination half-life after a single intrathecal bolus injection or short-term infusion of 50–136 micrograms is 1–5 hours, with high variability between and within patients; its half-life at cerebrospinal fluid steady state has not been determined.