Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Return to emergency care immediately for vomiting blood, black stools with weakness or fainting, severe breathing difficulty, a seizure, inability to wake, confusion that is getting worse, or very little to no urine.
If there is an immediate risk of further self-harm, contact emergency services or the appropriate crisis service now.
And for anyone, someone who:
Seek prompt medical advice for new fever, sore throat, mouth ulcers, unusual bruising, worsening weakness, reduced urination, persistent vomiting, abdominal pain, rash, or yellow skin or eyes.
Follow-up may include repeat blood counts and tests of kidney or liver function.
Attend these appointments even if symptoms have resolved, because some abnormalities can develop later.
If the overdose may have been intentional, follow-up should also address emotional safety.
A clinician can help arrange crisis support and mental health care.
And for anyone, someone who:
The article also says
Follow the discharge plan provided by the treating clinician or poison center.
Ask before restarting NSAIDs, aspirin, blood thinners like warfarin or apixaban , or other medicines that may affect the kidneys or bleeding risk.
Do not take another person’s medicine or substitute a veterinary product.
After an accidental exposure, store all human and veterinary medicines in their original containers, locked away from children and separated from food.
Dispose of old phenylbutazone through a pharmacy or approved medicine take-back program rather than keeping it for possible future use.
Every sign above is quoted from the sofidex article on Butazolidin overdose. If you are not sure, err upward — it is always reasonable to be checked.