Intrathecal Baclofen Withdrawal
/Gottula, A., Gorder, K., Peck, A., Renne, B. (2019). Dexmedetomidine for Acute Management of Intrathecal Baclofen Withdrawal The Journal of Emergency Medicine https://dx.doi.org/10.1016/j.jemermed.2019.09.043
Baclofen (beta-[4-chlorophenyl]-GABA) is an agonist at the beta subunit of gamma-aminobutyric acid (GABA) on neurons at the spinal cord level and brain presynaptically inhibiting calcium influx to prevent excitatory neurotransmitter release, and postsynaptically increasing potassium efflux, resulting in hyperpolarization and neuronal inhibition with resultant relief of spasticity.
Often oral baclofen dosing is insufficient and intrathecal baclofen (ITB) is required to achieve the desired effects. Unfortunately, ITB withdrawal is feared adverse event experienced by up to 40% of ITB patients. ITB withdrawal is characterized by increased spasticity, hypertension, tachycardia, hyperthermia, altered mental status, and seizures. In the most severe cases, autonomic instability, rhabdomyolysis, diffuse intravascular coagulopathy, multisystem organ failure, and death can occur. ITB withdrawal is clinically difficult to distinguish from sympathomimetic toxidromes, serotonin syndrome, or other GABA agonist withdrawal syndromes.
Benzodiazepines or propofol are the most common therapies for ITB withdrawal, but often require large doses to achieve clinical effect leading to obtundation, respiratory failure, and hemodynamic compromise. Dexmedetomidine has previously been reported in the treatment of oral baclofen withdrawal, leading to significant improvement in symptoms without suppressing respiratory drive. Dexmedetomidine offers a superior respiratory safety profile in comparison to benzodiazepines and propofol. Dexmedetomidine has a documented benefit in the setting of alcohol withdrawal, another GABA-mediated process, there is only a single case report of successful management of ITB withdrawal in the critical care environment, and this was for a perioperative pediatric patient who was already intubated and was being concomitantly treated with oral baclofen and i.v. lorazepam. (1) Dexmedetomidine acts on alpha-2 adrenergic receptors, inhibiting the release of norepinephrine presynaptically and sympathetic activity postsynaptically. In our patient dexmedetomidine was used to successfully treat her ITB withdrawal without obtundation, respiratory failure, or hemodynamic compromise.
Emergency physicians should be aware of dexmedetomidine as a promising option for the treatment of ITB withdrawal in the acute setting. Although little evidence is currently present, dexmedetomidine was used successfully in this case, and should be considered as a temporizing treatment for ITB withdrawal.
References
1.) Morr, S., Heard, C.M., Li, V. et al. Neurocrit Care (2015) 22: 288. https://doi.org/10.1007/s12028-014-0083-8
Authorship
Written by Adam Gottula, MD, Amanda Peck, PharmD
Editing and Posting by Jeffery Hill, MD MEd
