Lofexidine (hydrochloride)

Lofexidine hydrochloride (Baq-168) is an orally active agonist of the imidazoline I1 receptor (imidazoline I1 receptor) (Ki: 1.9 nM) and α₂-adrenergic receptor (α2-adrenergic receptor). Lofexidine hydrochloride binds to the α₂A-adrenergic receptor, reduces sympathetic outflow, lowers blood pressure, and exhibits vasoconstrictive effects. Lofexidine hydrochloride regulates the expression of c-fos and alleviates opioid withdrawal symptoms. Lofexidine hydrochloride is applicable to research on opioid addiction and withdrawal^[1][2]. In Vitro:Lofexidine hydrochloride binds to α₂-adrenergic receptors in rat brain cell membranes, with a K_d value of 5.5 nM^[1].
Lofexidine hydrochloride induces peripheral vasoconstriction in isolated rabbit ear central artery specimens^[1].
Lofexidine hydrochloride attenuates norepinephrine-induced contraction responses of isolated vas deferens specimens in a concentration-dependent manner^[1]. In Vivo:Lofexidine (administered via duodenal route; administered via intrathecal route) hydrochloride induces sustained, predictable hypotension in rats, with more prominent cardiovascular effects observed after intrathecal administration^[1].
Lofexidine (Intravenous administration) hydrochloride induces a transient hypertensive response followed by sustained hypotension in dogs and cats, whereas oral administration only causes hypotension^[1].
Lofexidine hydrochloride reduces the expression of Fos protein in the locus coeruleus of morphine-addicted mice during opioid withdrawal^[1].
Lofexidine (p.o.) hydrochloride induces reversible neurological symptoms in rats and dogs, with an LD₅₀ of 70-147 mg/kg in rats^[2].