Baclofen-induced neurotoxicity in patients with compromised renal function: Review

Baclofen is a centrally-acting γ-amino butyric acid agonist used mainly in the symptomatic management of spasticity originating from the spinal cord. It is absorbed completely from the gastrointestinal tract, metabolized by the liver to a minor degree, and excreted unchanged by the kidneys. Baclofen is moderately lipophilic and can cross the blood-brain barrier easily. At the usual dosage, it acts mainly at the spinal level without central nervous system (CNS) side effects. During renal failure, however, the elimination of the drug will decrease with a prolonged half-life, resulting in a larger area-under-the-curve exposure and disproportionate CNS toxicity. Clinically, these patients with renal failure may present with a variety of toxic symptoms manifesting at therapeutic/sub-therapeutic doses of baclofen. In cases of unexplained mental status changes in a patient receiving baclofen therapy, a careful assessment of renal function and a high suspicion of baclofen-induced encephalopathy will be key to the diagnosis.
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