If someone drinks too much or has an adverse reaction while drinking, it is very important they receive professional help as soon as possible. Quick responses can save lives...
Stay with the person until the ambulance arrives.
Ensure the person gets enough air by keeping crowds back and opening windows. Loosen tight clothing. Keep them warm- use blankets or a coat (but not too warm).
If the person is unconscious, don't leave them on their back - they could choke. Clear any vomit away from their mouth.
Turn them on their side and into the recovery position. Gently tilt their head back so their tongue does not block their airway.
If breathing has stopped, give mouth-to-mouth resuscitation. If there is no pulse, apply CPR.
Provide the ambulance officers with as much information as you can - what they have been drinking, how much they have been drinking, and any pre-existing medical conditions that you know the person has.
Give someone fluids (even water) if you think they're in shock or unconscious.
Leave someone alone, especially if they are unconscious.
If the person is asleep and you are unable to wake them up.
Look at the person's skin. If it is cold, clammy, pale, bluish in colour.