LORELAI: Sleep in? Luke?
RACHEL: Oh believe me, it wasn’t easy to get him to agree to it, but in the end, a little sweet talk, a couple of Excedrin PM he finally caved.
Excedrin is a brand of painkillers suitable for headaches, sold over the counter; it contains a mixture of paracetamol, aspirin, and caffeine. It is one of the most popular OTC pain medications in the US. Excedrin PM is paracetamol combined with an antihistamine that makes you drowsy. It’s been produced since 1969.
The fact that the diner opens for business at 6 am, that Luke lives over the diner, and for Luke, sleeping in means he stays in bed until past 6 (only possible because Rachel is there), means that it would never have been possible for him to stay up all night painting with Lorelai as they planned in That Damned Donna Reed, nor would it have been possible for Lorelai to paint the diner alone in the early hours of the morning without waking him.