Antihistamine

[Garmard]

Why do hayfever pills make me tired, almost to the point of going to sleep?

[Greedyfly]

Do you get the non drowsy ones? lol

[Sqad]

It is the side affect of almost all antihistamines.

[Greedyfly]

You could try a nasal spray instead maybe? I have to use both and eye drops its a nightmare

[Garmard]

I've tried the ones with Loratadine in but still has the same effect. Now i take them at bedtime instead as it's the only place i can fall asleep and not get into trouble...lol!

[Sqad]

Generally speaking....the better the antihistaminic effect, the worse the drowsiness.
The less drowsiness, the less the antihistaminic effect.

[Garmard]

What causes it sqad?

[Sqad]

Garmard I am not a pharmacologist, but the action of antihistamines is multi organ, but the sedative effect is due to their reaction on certain receptors in the brain and of course AH are used as sedatives for children in particular. I am sorry that my explanation is rather superficial, but i hope there might be someone on AB who has an expert knowledge of pharmacodynamics.

[york310]

The anti-histamine is non-specific and not only binds to the histamine receptors but also binds to the acetylcholine receptors in your body. This slows down the reuptake of acetylcholine leading to drowsiness. Acetylcholine is involved in many neurotransmitters in muscles (including the heart) and the brain.

[carlton23]

Oh yeah, of course, we all know that yorky!!!!!