Mechanism of action Enkephalins are peptides produced by the body that act on opioid receptors with preference for the δ subtype. Activation of δ receptors inhibits the enzyme adenylyl cyclase, decreasing intracellular levels of the messenger molecule cAMP. The active metabolite of<unk> , thiorphan, inhibits enkephalinase enzymes in the intestinal epithelium with an IC50 of 6.1 nM, protecting enkephalins from being broken down by these enzymes.<unk>  itself is much less potent at 4500 nM.) This reduces diarrhea related hypersecretion in the small intestine without influencing basal secretion.<unk>  also has no influence on the time substances, bacteria or virus particles stay in the intestine. Pharmacokinetics Some metabolites of<unk> .top left: precursor to the active metabolitetop right: active metabolitebottom row: inactive metabolites<unk>  is rapidly absorbed after oral administration and reaches Cmax within 60 minutes. Food delays Cmax by 60 to 90 minutes but does not affect the overall bioavailability.<unk>  is rapidly and effectively metabolized to the moderately active S-acetylthiorphan the main active metabolite thiorphan, of which 90% are bound to blood plasma proteins. In therapeutic doses,<unk>  does not pass the blood–brain barrier. Inhibition of enkephalinases starts 30 minutes after administration, reaches its maximum (75–90% inhibition with a therapeutic dose) two hours after administration, and lasts for eight hours. The elimination half-life, measured from enkephalinase inhibition, is three hours. Thiorphan is further metabolized to inactive metabolites such as the methyl thioether and the methyl sulfoxide. Both active and inactive metabolites are excreted, mostly via the kidney (81.4%), and to a lesser extent via the feces (8%).
Racecadotril
Moexipril
Spirapril
Ramipril
Macitentan
Methallenestril
Ambrisentan
Oprelvekin