If a paracetamol overdose is suspected, hospital treatment should be sought without delay. Ideally within 12 hours of having taken the overdose. Treatment must always be supervised in a hospital. The recommended dose of paracetamol for a single adult is two standard 500 mg tablets.Researches have reported that the threshold for liver damage to start from a single paracetamol overdose is 15 gms (30 tablets).f you are someone you know has had an overdose of paracetamol then whether to not symptoms start to surface you should visit the doctor. Earlier the better. Best within one hour of intake of it. And starts getting really dangerous after 24 hours of having taken he overdose.