How do you deal with a medicine that says "take one every 6 hours"?

I had a root canal on Tuesday and I’m on a antibiotic course of treatment. I cannot find 4 intervals of 6 hours in a day that I am awake. The first night I took one in the middle of the night but that screwed up my sleep.

I’ve decided to only take 3 a day; morning, afternoon and before bed. Is this a bad idea?