Calculators for Paracetamol Toxicity in Adults & Children 

Only intended for use by EKHUT healthcare professionals - interpret results in patient context

This calculator implements the MHRA advice of the 3rd September 2012.
Please be aware that there is the potential for confusion as out of date information is available which would lead to undertreatment.

What is patient's current plasma paracetamol concentration ?  
How many hours since patient took single potential overdose of paracetamol (minimum 4 hours)? hours 
 

Do not use this calculator in patients who have taken staggered overdoses as it is meaningless. Such patients should all be considered for treatment with acetylcysteine.

 Enter weight of patient  kg

    

Acetylcysteine should be administered by intravenous infusion preferably using Glucose 5% as the infusion fluid. Sodium Chloride 0.9% solution may be used if Glucose 5% is not suitable. The full course of treatment with acetylcysteine comprises of 3 consecutive intravenous infusions. Doses should be administered sequentially with no break between the infusions. Adult patients should receive a total dose of 300 mg/kg body weight over a 21 hour period.



1)  WHAT ARE THE CHANGES IN THE UK THAT WERE IMPLEMENTED ON 3rd September 2012?

The main changes were that only a single dosing line is used in the nonogram , very similar to that used in the past for high risk patients (over treatment is safer than undertreatment), all staggered overdoses should be treated (long trust policy) and the first dose of acetylcysteine iv is given over 1 hour rather than 15 minutes (infusion rate for first infusion one quarter that shown in this calculator for new recommendations). One single UK recommendation for children now exists. The other change is that a simplified table was introduced based on bands of weight. The calculator above is accurate to within 1ml (200mg) of acetylcysteine as specified in this table but may not always agree with the simplified table as the rounding decisions in the table tend towards over treatment. No harm is expected to result from which ever source you use, but please report any such possible issues as clinical incidents. For children more exact calculations are undertaken but again can vary from the simplified tables due to rounding decisions. It is possible that the more exact calculation ability of our calculator has fluid load advantages for children less than 5kg.   The exact infusion values for a weight to a decimal place can be calculated by clicking the following button and the results displayed above. This may be useful in very small children or in complex adult patients where fluid load is wished to be minimised while definitely delivering the recommended treatment dose 

2)  WHO CAN I USE THE CALCULATORS ON?

The paracetamol toxicity calculator should only be used where a single timed overdose has taken place. The acetylcysteine calculator is intended to simplify calculation of infusion rates and amounts of fluids for adults and children over 1kg. Users are expected to check that the results of calculations are reasonable and appropriate for the clinical context. This can be done from weight based infusion charts such as those published by the MHRA which users can safely use instead of this calculator. While other web based calculators exist they may not have been updated to the UK MHRA recommendations or may be other countries recommendations. See also BNF and manufacturers information .

3)  WHAT IS THE RELEVENT INFORMATION FOR THOSE PATIENTS I CAN USE CALCULATOR ON?

Refer to the manufacturers information ( an example is Parvolex® Injection SPC) for full details. Please note that information from some manufacturers had not been updated by September 2012.

4)  WHO DID THIS?

An acetylcystine dose calculator was first developed by Fernando Candal Carballido, Senior Staff Nurse in Accident and Emergency, William Harvey Hospital, Ashford, Kent without whose idea you would not have this web based calculator. The paracetamol toxicity calculator is adapted from one developed by the eBNF but with better error condition detection and quite different coding. The code for this calculator is freely available to examine as it is javascript.