Author: Nick Holford

Background High dose methotrexate (MTX) is the mainstay of treatment for many cancers. It is typically administered on repeated occasions known as ‘cycles’.  Due to extensive variability in its pharmacokinetics (PK) and life-threatening toxicity, the use of repeated MTX concentration measurements to determine the duration of  leucovorin dosing has decreased the incidence of severe toxicity.  […]

A web based collaborative tool has been developed for helping with dose individualisation. It has been applied to dosing busulphan for conditioning prior to marrow transplantation. NextDose stores patient information seperately from the web interface for security. This information is stored in a non-identifiable format and requires authorised use of the NextDose application to combine […]

  Objectives: To describe the maturation of fat free mass (FFM) from prematurity to adulthood as a function of postmenstrual age (PMA) using nonlinear mixed effect modeling. Background:  A model for FFM for adults has been well described, with different formulae for males and females (1).  An extension to this model using data from age 3 […]

A common challenge for pharmacokinetic modellers is what to do with measurements that are known to be less than the lower limit of quantification (LLOQ). These measurements are, unfortunately, often recorded as BLQ (Below Limit of Quantification), even though the chemical analyst was able to quantify the measurement below this limit. The limit is defined […]

Objectives: To evaluate pharmacokinetic models for prediction of morphine doses from premature neonates to adults. Design: External evaluation of published models for morphine clearance by comparison with literature reports of morphine clearance in individual patients and healthy subjects. Main Outcome Measures: Prediction of morphine dose rate in premature neonates, full term neonates, infants, children and […]