It's a long time I haven't been able to find a movie I've seen in the early/mid '90s.
It was a police/action movie, where the protagonist was actually able to do all the action cool stuff because he was an addict to some sort of stimulant, and his partner was a lesbian.
It struck me because it was the first time in such a movie where the "almost-superhuman" abilities of the main character, instead of being taken for granted, are explained because he was basically cheating with drugs, and I thought this was quite original. Also the presence of a lesbian partner will likely narrow it down enough, hopefully.
(the only detail left is that I've watched it in Italian, though I strongly doubt there is a movie which matches all of the above, but just not this last detail)