Of Medicines and Sleep-Aids

I couldn't sleep last night because of my allergies. My nose felt so plugged up that I had to take antihistamines (which caused drowsiness). Sure I was able to sleep, but I didn't dream at all. The time I woke up, I felt like I didn't sleep at all. It felt like I closed my eyes for a minute then it's time to wake up.

Now that I thought about it, when I take medicines at night, those are the times that dreams don't visit me. Could there be a correlation between taking medicines when we go to sleep and dreaming and why? Now, that'd be an interesting theory. Let's put that to the test, shall we?