Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call 911 immediately if the person is difficult to wake, has a seizure, collapses, has trouble breathing, or has taken doxepin intentionally.
Elsewhere, call your local poison centre or emergency number.
Routine follow-up happens after emergency care.
And for anyone, someone who:
New fainting, seizures, breathing difficulty, or marked confusion after discharge require urgent reassessment.
Seek follow-up advice for ongoing tiredness, cough after vomiting, muscle pain, reduced urination, or concerns about restarting medicines.
And for anyone, someone who:
The article also says
Any known or possible doxepin overdose needs immediate professional advice, even if there are no symptoms.
In the United States, call Poison Control at 1-800-222-1222 .
While waiting for help:
Do not make the person vomit
Do not give food, drink, charcoal, or another medicine unless instructed
Do not let the person drive
Keep the medicine container or packaging for responders
Place an unconscious but breathing person on their side if safe
Start CPR if they are not breathing and you know how
If an intentional overdose may have occurred, stay with the person if it is safe.
Remove access to remaining medicines without putting yourself at risk.
Every sign above is quoted from the sofidex article on Doxepin overdose. If you are not sure, err upward — it is always reasonable to be checked.