Is there such a thing as a prescription for probiotics like what's in yogurt?

Yes: There are a couple of different types of pharmaceutical grade high dose probiotics. One is called vsl #3 (also in double strength form) and another called align. Like different kinds of yogurts, kefirs, etc., each has its own formulation of friendly, "good" bacteria that help maintain a more normal bacterial balance in the intestine. I'm sure there are other brands that i'm not aware of.

Probiotics: There are a number of pharmaceutical grade probiotic supplements available - (Without a prescription).