Sedation
"I started taking phenergen to assist with ongoing bad allergies (to dust mite and pollen) and found it very effective for this as well as guaranteeing me a good night sleep. I only take a 10mg dose about 1 hour before bed and no later than 8pm if I want to wake early for exercise before work. I find if I take it any later I am lethargic at 0530 and take a bit to get going.
I have also used the syrup for my young boys as a rare sleep aid. Both my husband (who was prescribed it when he had an allergic reaction to penicillin) and eldest 5 yo are affected by this antihistamine/sleep aid. It makes them groggy and crabby the next day. My youngest (3yo) and I have only positive effects from it."