- flu oro eth yl ) am ph et am ine ▁( DO EF ; ▁also ▁known ▁as ▁dim eth ox y flu oro eth yl am ph et am ine ) ▁is ▁a ▁less er - known ▁psych ed el ic ▁drug ▁and ▁member ▁of ▁the ▁DO x ▁class . ▁DO EF ▁was ▁first ▁synth es ized ▁by ▁Alexander ▁Sh ul gin . ▁In ▁his ▁book ▁Pi H K AL , ▁the ▁dos age ▁range ▁is ▁listed ▁as ▁ 2 – 3 . 5   m g , ▁and ▁the ▁duration ▁is ▁listed ▁as ▁ 1 2 – 1 6 ▁hours . ▁Very ▁little ▁data ▁exists ▁about ▁the ▁ph arm ac ological ▁properties , ▁met abol ism , ▁and ▁to x icity ▁of ▁DO EF . ▁ ▁References ▁ ▁Category : Sub st it uted ▁am ph et am ines ▁Category : F lu oro eth yl ▁comp ounds <0x0A> </s> ▁Se ast alk er ▁is ▁an ▁interactive ▁fiction ▁game ▁written ▁by ▁Stu ▁Gal ley ▁and ▁Jim ▁Lawrence ▁and ▁published ▁by ▁Info com ▁in ▁ 1 9 8 4 . ▁It ▁was ▁released ▁simultaneously ▁for ▁several ▁popular ▁computer ▁platforms ▁of ▁the ▁time , ▁such ▁as ▁the ▁Com mod ore ▁ 6 4 , ▁Apple ▁II , ▁and ▁IBM ▁PC ▁compat ibles ▁( as ▁a ▁self - boot ing ▁disk ). ▁The ▁game ▁was ▁market ed ▁as ▁an ▁introduction ▁to ▁interactive ▁fiction ▁for ▁pre teen ▁players , ▁having ▁difficulty ▁rating ▁of ▁" J un ior ." ▁It ▁was ▁the ▁only ▁game ▁to ▁ever