Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services if you or someone with you has:
New severe confusion or cannot be woken normally
A seizure
Collapse or fainting
Chest pain with a fast, slow, or irregular heartbeat
Severe weakness that makes standing or walking unsafe
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek same-day medical advice if you have repeated vomiting, signs of dehydration, much less urine than usual, worsening weakness, or marked drowsiness.
Prompt assessment is also appropriate if a recent blood test shows high calcium or worsening kidney function.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you regularly use calcium carbonate and develop ongoing constipation, nausea, increased thirst, frequent urination, unusual tiredness, or difficulty concentrating.
These symptoms have many possible causes, but blood tests can check calcium and kidney function.
The article also says
Bring supplement and medicine containers to the assessment if this can be done without delaying care.
Every sign above is quoted from the sofidex article on Milk-alkali syndrome. If you are not sure, err upward — it is always reasonable to be checked.