# antihistamine

A medicine that blocks histamine, a chemical that helps keep you awake. Some older ones make you drowsy and are sold as nighttime sleep aids.

## Where it comes up

- [Why do my legs feel restless at night?](https://nitez.com/restless-legs)
- [Why is it so hard to sleep while pregnant?](https://nitez.com/pregnancy-and-sleep)

https://nitez.com/words/antihistamine