Objective-(1) To see whether children are weighed before drugs are pre
scribed in an accident and emergency (A&E) department; (2) to assess h
ow safe it is for doctors to guess children's weight if they prescribe
''by eye''. Methods-An audit of 100 sets of notes was performed to se
e if children were weighed a before drugs were prescribed. A&E senior
house officers were asked to estimate the weight of 75 children aged 1
2 years and under. Results-Children were weighed before prescribing in
only two out of 100 cases. The mean difference between the actual and
estimated weights was -0.21 (not significantly different from zero; P
= 0.40); 95% of the estimates were within two standard deviations of
the mean difference. The percentage difference between the actual and
estimated weight varied between overestimates of 300% and underestimat
es of nearly 100%. Conclusions-The average guess of doctors as a group
was approximately correct. However, there was a wide range of estimat
es for individuals. If the child's weight is guessed, the doctor could
risk under- or overprescribing analgesia, sedation, or intravenous fl
uids. Given the wide range of estimates, actual weights are required f
or accurate prescribing. Prescribing on an age basis may be acceptable
for drugs such as paracetamol or amoxycillin, but it is imperative to
prescribe on a mg/kg basis for opiates, sedatives, and intravenous fl
uids because of the large variation in weight that can occur for a sin
gle age.