184025-19-2

Ciproxifan is a histamine H₃ receptor antagonist (K_i = 0.5 nM for inhibition of histamine release in rat synaptosomal preparations). It is selective for histamine H₃ over histamine H₁ and H₂, M₃ muscarinic, and α_1D- and β₁-adrenergic receptors (K_is = 3.15-25 μM), as well as the serotonin (5-HT) receptor subtypes 5-HT_1B, 5-HT_2A, 5-HT₃, and 5-HT₄ (K_is = 1.58-15 μM) in radioligand binding assays. Ciproxifan (3-300 nM) inhibits relaxation in precontracted isolated guinea pig ileal longitudinal muscle induced by R-(–)-α-methylhistamine . In vivo, ciproxifan reduces R-(–)-α-methylhistamine-induced water consumption in rats (ED₅₀ = 0.09 mg/kg). It increases wake episode duration and latency to fall asleep in rats when administered at a dose of 2 mg/kg.

Ciproxifan is a potent histamine H3 receptor antagonist which affects histamine levels in the brain. It may be used in treatments for sleep and neurological disorders.

Potent, selective H3 histamine receptor antagonist.