N-Desmethyl Pimavanserin is the active metabolite of Pimavanserin. Pimavanserin is a selective inverse agonist of the 5-HT2A receptor with pIC50 and pKd of 8.73 and 9.3, respectively.In Vitro: The mean plasma half-lives for Pimavanserin and its metabolite N-Desmethyl Pimavanserin (AC-279) are 57 hours and 200 hours, respectively.