Clinical Relevance of Pharmacological and Physiological Data in Intrathecal Baclofen Therapy

ObjectiveTo review all pharmacological and physiological data available on intrathecal baclofen (ITB) therapy and to evaluate its use in clinical practice and future research.Data SourcesPubMed was searched for relevant anatomic, physiological, and pharmacological data available on ITB.Study SelectionAll currently available data on ITB pharmacokinetics (PKs) and pharmacodynamics (PDs) in both human and animal studies were reviewed and combined with the anatomy and physiology of the intrathecal space and cerebrospinal fluid flow.Data ExtractionOnly 4 studies reported PK data on ITB in humans. More studies reported PD data on ITB; however, none were combined with PK data. More detailed data on PK could be gathered from studies using an animal model.Data SynthesisITB does not spread equally over the intrathecal space after injection, but it diffuses according to a concentration gradient. ITB distribution can be influenced by the location of the catheter tip and by changing the infusion mode.ConclusionsThe pharmacological and physiological data on ITB can be used to support decisions in clinical practice concerning drug concentration, infusion regimens, localization of the catheter tip, and management of tolerance; however, some strategies have little evidence in humans.