Patient specifics

Sometimes the dose is based on a specific of the patient such as:

  • mg/ kg – this where the second number is the weight of the patient (often used in children)
  • mg/ m2 – this is where the second number is the body surface area of the patient (most likely in children, the elderly or chemotherapy)
  • Ideal body weight. This is used for drugs that are totally or almost totally water soluble and so the volume of distribution for the drug is not increased in a fatter patient. A favourite example is gentamycin.