My son took my dose of rtanna by mistake. He thought it was his allergy medicine. He is 8 and weighs 90/95 lbs. He took 2 tablets

Probably nothing. Phenylephrine is a short-acting and weak decongestant and chlorpheniramine is a weak and short-acting antihistamine. Just watch him for a little bit but nothing should happen.
Anytime. Anytime your child eats or drinks something she shouldn't have, you can call the poison control center toll-free for advice. 1-800-222-1222 this is the number even er doctors and pediatricians use for the most up-to-date advice and treatments for ingestions. If your child is having trouble breathing or is in severe distress after eating something she shouldn't have, this would be a reason to call 911 and go to the er instead. Legal disclaimer: I am providing this general and basic information as a public service and my response to this question does not constitute a doctor-patient relationship. For any additional information, advice, or specific concerns, please speak with your own physician. The information provided is current as of the date of the answer entry.