It's the Walgreens store-brand version of a Moe Greene Special.
Kind of like when Moltasanti says "Lucas Brazzy sleeps with the fishes."
I think the "Godfather" outtakes went something like this:
Moe Greene: Do you know who I am? Michael Corleone: Mulgreen? Moe Greene: You goddamn Ginny's really make me laugh. I was going to Walgreens when you were going out with cheerleaders.