Baclofen-d4 is the deuterium labeled Baclofen. Baclofen, a lipophilic derivative of γ-aminobutyric acid (GABA), is an orally active, selective metabotropic GABAB receptor (GABABR) agonist. Baclofen mimics the action of GABA and produces slow presynaptic inhibition through the GABAB receptor. Baclofen has high blood brain barrier penetrance. Baclofen has the potential for muscle spasticity research[1][2][3].