Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Elsewhere, contact your local poison information centre or emergency medical service.
Have the medicine container available if possible.
Call emergency services now if the person:
Begin CPR if they are not breathing normally and follow instructions from emergency services.
Routine follow-up is appropriate after emergency treatment if there are questions about restarting medicine, persistent mild tiredness, movement symptoms, or prevention of another medication error.
And for anyone, someone who:
New fainting, breathing difficulty, seizures, worsening confusion, or severe stiffness is not routine and requires urgent reassessment.
And for anyone, someone who:
The article also says
Any suspected phenothiazine overdose needs immediate expert advice, even if the person feels well.
Symptoms and ECG changes can develop after the tablets were swallowed.
In the United States, call Poison Help at 1-800-222-1222 .
Do not leave the person alone.
Do not make them vomit, give food or drink to a drowsy person, or let them drive to hospital.
Place an unconscious but breathing person on their side if it is safe to do so.
Every sign above is quoted from the sofidex article on Phenothiazine overdose. If you are not sure, err upward — it is always reasonable to be checked.