Anti-histamines

[Stottpot]

Hello,
Following on from a podcast regarding peri menopause, I started to take anti-histamines to aid sleep. In the Hormone Repair manual it also talks about the high histamine state which can effect mood and sleep (Chapter 4). The anti-histamines have really helped with my sleep! Are they OK to take long term? What risks do I need to be aware of? Is it OK to take them daily? I have just been taking the over the counter ones with no adverse side effects. I'm concerned that they dampen down the nervous system which can't be good longer term. Any thoughts?
Thank you.