If you are positive that you have given your child too much of any OTC medicine, it's best to call the Poison Control Center at 1-(800)-222-1222. The trained professional on the other end of the line will be able to determine whether your child is in danger or not. Many OTC medicines are harmful in large quantities beyond the recommended dose. If your child is experiencing any of the following, you should call 911 immediately: Stops breathing. Won't wake up. Displays very strange behaviors. Can't swallow. Shakes or twitches uncontrollably. Experiences facial swelling. Develops a rash that spreads quickly.