Glycine receptor agonists are medications that act as agonists of the glycine receptor. They are compounds that bind to and activate the inhibitory glycine receptor (GlyR), a chloride-permeable ligand-gated ion channel that mediates fast synaptic inhibition primarily in the spinal cord and brainstem. [1] The natural neurotransmitter glycine is considered a full agonist with maximal efficacy, producing an open probability exceeding 95% when the receptor is fully occupied. [2] Partial agonists such as taurine and β-alanine produce submaximal responses compared to glycine, with taurine eliciting approximately half the maximum open probability response. [2] Recent research has identified aminomethanesulfonic acid (AMS) as a potent glycine receptor agonist that is structurally intermediate between glycine and taurine, achieving a maximum single-channel open probability of 0.85 at acidic pH conditions where it remains chemically stable. [2] Contemporary research has focused on developing positive allosteric modulators (PAMs) of glycine receptors as potential therapeutic agents for chronic pain conditions, given that enhanced glycinergic inhibition can provide analgesia. [3] The tricyclic sulfonamide compound AM-1488 has emerged as a prototypical glycine receptor PAM that also exhibits direct agonistic activity, with oral administration at 20 mg/kg reducing allodynia in mouse models of neuropathic pain comparable to pregabalin treatment. [4]