That's a good question. I've got a feeling that most people never look at the instructions that come with almost every medication that have all that good information 🙃 I was one of them and my original prescribing doctor was long gone as I get a new resident PCP every two years or so. After the pharmacist told me I should be taking them at night, I confirmed it with my PCP and was happy that it improved my nightly wake up calls.