Hi D.,
I would be concerned with that amount of medicine in a 2 yr old. Prescription meds are are way over prescribed. My son ( we call him the mucus man) has severe coughing from mucus drainage. He had some episodes so severe that even broke blood vessels in his eyes! We tried all the drugs both prescription and otc, from allergy, decongestants, antihistamines, cough suppressants, and asthma- and nothing really brought the releif he needed and I had to sit him up with many pillows at night. What I ended up doing for the past 7 yrs that gets him through the night without coughing fits is this: air purifier, humidifier, and sprinkles of Olbas oil all around him. I get it at Vitamin Shoppes and health food stores. Vicks wasn't strong enough but it is also worth a try.
I know the vicks on the feet seems a bit strange to me, BUT, I have been putting it on my own feet for about 2 months (desperate attempt to get rid of fungus...) and I haven't gotten sick at all, yet 4 of my family members have all been sick, coughing and hacking around me. After reading the other post about rubbing it on the feet, I have to start thinking there may be something very special about camphor, menthol, and eucalyptus! Anyway, it can't hurt and is drug free. Please read up on the possible side effects of the drugs. Recently they put my son on Singulair, then we found out it is linked with suicidal tendancies--no thanks!
Good luck, I know how exhausting all that coughing can be.
-L.