4,4,6,6,14,14-hexadeuterio-5-nitroso-2,5,19-triazatetracyclo[13.4.0.02,7.08,13]nonadeca-1(15),8,10,12,16,18-hexaene,4,4,6,6,14,14-hexadeuterio-5-nitroso-2,5,19-triazatetracyclo[13.4.0.02,7.08,13]nonadeca-1(15),8,10,12,16,18-hexaene,Mirtazapine Metabolite