Difelikefalin (CR845) is an agonist of kappa opioid receptors (KORs) useful in the treatment of pruritus secondary to chronic kidney disease. KORs were first associated with itching in 1984.[A237610] Further investigations revealed that dynorphins, endogenous…

Gabapentin is a structural analogue of the inhibitory neurotransmitter gamma-aminobutyric acid ([GABA]) that was first approved for use in the United States in 1993.[L8717] It was originally developed as a novel anti-epileptic for the treatment of certain typ…

Gabapentin enacarbil is marketed under the name Horizant. It is a prodrug of gabapentin, and indicated in adults for the treatment of Restless Legs Syndrome (RLS) and postherpetic neuralgia (PHN).