Famotidine-d 4

Famotidine -d 4 (MK-208-d 4 ) is the deuterated-labeled Famotidine. Famotidine (MK-208) is an orally active and highly selective histamine H2 receptor antagonist. It inhibits gastric acid secretion by blocking the Gs signaling pathway, and regulates intracellular cAMP and ERK pathways. Famotidine inhibits TLR3 -mediated inflammatory pathways, and reduces the expression of various inflammatory mediators and interferon-related genes. Famotidine scavenges DPPH and nitric oxide free radicals, alleviates oxidative stress damage in gastric tissue, inhibits proMMP-9, improves vascular endothelial permeability, and restores the normal physiological functions of neutrophils and eosinophils. Famotidine crosses intestinal epithelial cells via facilitated diffusion and passive diffusion, blocks paracellular cation transport, and increases intestinal transepithelial electrical resistance. Famotidine reduces serum levels of transaminases and alkaline phosphatase, exerts analgesic effects and gastric protective effects simultaneously. Famotidine can be used in studies related to COVID-19, liver injury and acute gastric ulcer ^{[1] [2] [3] [4] [5]}.

References:
[1]. Mukherjee R, et al. Famotidine inhibits toll-like receptor 3-mediated inflammatory signaling in SARS-CoV-2 infection. The Journal of biological chemistry. 2021 Aug;297(2):100925.
[2]. Malone RW, et al. COVID-19: Famotidine, Histamine, Mast Cells, and Mechanisms. Frontiers in pharmacology. 2021;12:633680.
[3]. Ahmadi A, et al. Hepatoprotective, antinociceptive and antioxidant activities of cimetidine, ranitidine and famotidine as histamine H₂ receptor antagonists. Fundam Clin Pharmacol. 2011;25(1):72-79.
[4]. Pradeepkumar Singh L, et al. Novel role of famotidine in downregulation of matrix metalloproteinase-9 during protection of ethanol-induced acute gastric ulcer. Free radical biology & medicine. 2007 Jul 15;43(2):289-99.
[5]. Lee K, et al. Saturable transport of H2-antagonists ranitidine and famotidine across Caco-2 cell monolayers. Journal of pharmaceutical sciences. 1999 Jul;88(7):680-7.