Naldemedine is a peripherally acting opioid receptor antagonist (IC50s = 1.15, 1.11, and 1.5 nM for recombinant human μ-, δ-, and κ-opioid receptors, respectively).1,2 It inhibits opioid-induced emesis and vomiting in ferrets and opioid-induced constipation in rats (ED50 = 0.03 mg/kg for both) without affecting the analgesic effect of morphine in the tail-flick test in rats.1 Naldemedine induces the opioid withdrawal symptoms of diarrhea and teeth chattering, but not jumping, in morphine-dependent rats when administered at doses of 1 and 3 mg/kg, respectively.2 Formulations containing naldemedine have been used in the treatment of opioid-induced constipation.

|1. Inagaki, M., Kume, M., Tamura, Y., et al. Discovery of naldemedine: A potent and orally available opioid receptor antagonist for treatment of opioid-induced adverse effects. Bioorg. Med. Chem. Lett. 29(1), 73-77 (2019).|2. Kanemasa, T., Koike, K., Arai, T., et al. Pharmacologic effects of naldemedine, a peripherally acting μ-opioid receptor antagonist, in in vitro and in vivo models of opioid-induced constipation. Neurogastroenterol. Motil. 31(5), e13563 (2019).