The Armalite AR-50 that languished on the shelf of the shop at which I worked back in '03 had its accessories displayed on the shelf next to it. Among those accessories was a little 2-pack of Advil tablets.
"Hey, that's 'cause your shoulder's gonna hurt so much after shootin' it, right?" was the usual comment when someone noticed the foil packet.
No, like most .50 BMG rifles, the weight and the muzzle brake combine to make felt recoil not noticeably worse than, say, heavy slug loads from a twelve bore fowling piece. The Advil is for the effects of the muzzle blast after you've fired more than a handful of rounds.
It's bad enough on a conventional fifty, where the long barrel places the muzzle brake in a separate ZIP code from the shooter; it's positively ferocious on a bullpup.