Dubious claim with bad reference
So, I noticed that this claim was made for both 2-fluorination & 4-fluorination, on the respective pages: "Studies demonstrate that 2-flourine amphetamine substitutions limit activity of the compound at the alpha-1 adrenergic receptor with an over 200-fold increased selectivity for A2 receptors over A1 receptors."
I decided to check the citation to see which one it supported, and realized that it was neither. The little bit about fluorinated norepinephrine is also pretty irrelevant in terms of SAR, so I think it was someone with a vested interest in selling these amphetamines attempting to justify the anecdotal effects / dose ceiling where applicable. I've removed the claim from the pages I noticed it in. Storm (talk) 04:59, 7 March 2017 (CET)