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 emergency services immediately if someone who may have taken meperidine:
Call emergency services even if the person wakes up.
Follow the dispatcher’s instructions, provide rescue breathing or CPR if trained, and give another naloxone dose if directed or if symptoms return.
For slow or stopped breathing, unconsciousness, or seizures, call emergency services first.
And for anyone, someone who:
Routine follow-up is appropriate after recovery to review medicines, kidney and liver health, pain care, mental health needs, and access to naloxone.
And for anyone, someone who:
The article also says
Give naloxone if it is available.
Place a breathing but unconscious person on their side if this can be done safely.
Stay with them.
Do not give food, drink, stimulants like methylphenidate or lisdexamfetamine , or a cold shower, and do not make them vomit.
In the United States, Poison Control can be reached at 1-800-222-1222.
Elsewhere, contact the local poison information service.
Every sign above is quoted from the sofidex article on Meperidine hydrochloride overdose. If you are not sure, err upward — it is always reasonable to be checked.