Children
The Royal College of Paediatrics and Child Health textbook Medicines for Children should be the standard reference source and doses are generally stated on a specific dose per kg basis. It is therefore essential for all children under 12 to be weighed prior to prescribing any medicines.
Notes:
Occasionally medicines are prescribed on a dose per age range basis or as a specific dose per surface area basis.
Adults
Generally a patients weight should be one of the factors considered when prescribing any medicine, but particularly for those with a narrow therapeutic index.
The following list contains individual or classes of medicines for which it is desirable that patients be weighed prior to prescribing.
It is good practice to calculate doses using an accurate weight but in an EMERGENCY situation, where it is impractical to weigh the patient, then it may be necessary to make an educated estimate of the patient's weight, confirmed with the patient (if possible). An accurate weight should be established as soon as possible thereafter.
Medicines in general use
Aciclovir IV
Aminophylline IV
Amiodarone IV
Azathioprine
Gentamicin
Heparin
Low Molecular Weight Heparins e.g. Enoxaparin
Phenytoin
Thrombolytics e.g. Tenecteplase
Tobramycin
Medicines in specialist use
Acamprosate
Amphoteracin IV
Anaesthetics IV
Anti-arrhythmics IV
Anti CMV and PCP agents IV
Antiretrovirals
Anti TB treatment
Beta blockers IV
Calcitonin (salmon)
Chemotherapy: body surface area may be required - refer to individual regimes
Ciclosporin
Co-trimoxazole IV (high dose for PCP)
Cyclophosphamide
Epoprostenol
Epoetin
Etanercept
Flucytosine
Glycoprotein IIb IIIa Inhibitors
Granulocyte colony stimulating factors (G-CSF)
Infliximab
Inotropes IV
Mefloquine
Metoclopramide IV high dose post chemotherapy
Muscle relaxants IV
Propafenone
Quinine IV
Salbutamol IV
Terbutaline IV
Vasoconstrictors IV
Vasodilators IV
Refer to BNF or individual product literature for dosing information
Medicines Management Committee
June 2003