Hi A.,
Medications are never tested on little ones (thank God) so no one really knows how a child will react to any of them. Doctors go with past experience from other meds, not much different that the ladies here sharing their experiences. ALL meds are synthetic and can contraindicate with anything that is your little one's system. It doesn't just have to be another drug. It could be the processing in a McDonald's hamburger. There is really no way to tell unless all things are taking into consideration. That means that this could be a stimulant to your child and put another child to sleep. It just depends.
I personally recommend removing as many stimuli as you can so your daughter's body doesn't have to try and fight these things off. Household chemicals weaken an immune system and part of that immune system strength is to give the ability to sleep restfully. We detoxed our home about 5 years ago and health and behavior changed for the better. I would specifically look at what is in her bedding and what you wash her sheets with. Most laundry detergents have some form of Chlorine bleach in them and that is a neurological toxin and stimulant.
Seasonal allergies are abnormal to the human body. They are regularly diagnosed that way because the natural things will cause problems if the immune system is too busy fighting off the synthetic things, from the chlorine bleach I mentioned to your perfume that your three year old cuddles up to. They all should be taken into account.
Regards,
M.