A creature can voluntarily lower its spell resistance. Doing so is a standard action that does not provoke an attack of opportunity. Once a creature lowers its resistance, it remains down until the creature’s next turn. At the beginning of the creature’s next turn, the creature’s spell resistance automatically returns unless the creature intentionally keeps it down (also a standard action that does not provoke an attack of opportunity).
Drinking a potion is a standard action, as such, a creature with SR cannot ever benefit from a curative potion (unless someone else feeds it to him, as a full-round action). How stupid is that?
Is it game-breaking to allow a creature to suppress SR in the first round, and then drink the potion in the second round, ignoring the SR?