I did hear there could be some problem from the two being co-located that they can counteract each other. Or at least that's what I thought I was told by someone who had that problem.
When I tried to transition the first time I was so paranoid about what the pharmacists would think, I would take my scripts to four different chemists, one each. I'd get Androcur from one (OMG, they must think I'm a sex criminal for needing this), Primogen Depot from another (they must think I'm a weirdo), etc, etc - I think if I'd tried to buy all four at the same pharmacy my brain would have exploded in dread. These days I don't care, get them all filled at once and don't care what they think - and that was when I was still in guy mode.