Loperamide (ADL 2-1294), an opioid antihyperalgesic agent with peripheral selectivity.

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DeHaven-Hudkins DL, Burgos LC, Cassel JA, Daubert JD, DeHaven RN, Mansson E, Nagasaka H, Yu G, Yaksh T

Loperamide (ADL 2-1294), an opioid antihyperalgesic agent with peripheral selectivity.

J Pharmacol Exp Ther. 1999 Apr;289(1):494-502.

PubMed ID

10087042 [ View in PubMed

]

Abstract

The antihyperalgesic properties of the opiate antidiarrheal agent loperamide (ADL 2-1294) were investigated in a variety of inflammatory pain models in rodents. Loperamide exhibited potent affinity and selectivity for the cloned micro (Ki = 3 nM) compared with the delta (Ki = 48 nM) and kappa (Ki = 1156 nM) human opioid receptors. Loperamide potently stimulated [35S]guanosine-5'-O-(3-thio)triphosphate binding (EC50 = 56 nM), and inhibited forskolin-stimulated cAMP accumulation (IC50 = 25 nM) in Chinese hamster ovary cells transfected with the human mu opioid receptor. The injection of 0.3 mg of loperamide into the intra-articular space of the inflamed rat knee joint resulted in potent antinociception to knee compression that was antagonized by naloxone, whereas injection into the contralateral knee joint or via the i.m. route failed to inhibit compression-induced changes in blood pressure. Loperamide potently inhibited late-phase formalin-induced flinching after intrapaw injection (A50 = 6 microgram) but was ineffective against early-phase flinching or after injection into the paw contralateral to the formalin-treated paw. Local injection of loperamide also produced antinociception against Freund's adjuvant- (ED50 = 21 microgram) or tape stripping- (ED50 = 71 microgram) induced hyperalgesia as demonstrated by increased paw pressure thresholds in the inflamed paw. In all animal models examined, the potency of loperamide after local administration was comparable to or better than that of morphine. Loperamide has potential therapeutic use as a peripherally selective opiate antihyperalgesic agent that lacks many of the side effects generally associated with administration of centrally acting opiates.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Loperamide	Kappa-type opioid receptor	Protein	Humans	Unknown	Agonist	Details
Loperamide	Mu-type opioid receptor	Protein	Humans	Yes	Agonist	Details