Sam Holford

Hi, I'm the PAGANZ web guy and an Obstetrics & Gynaecology registrar at Auckland Hospital. I dabble in the practical aspects of improving dosing through development of NextDose.

Author Archive | Sam Holford

From the First to the NextDose: My journey through 20 years of PAGANZ

Our overarching aim has been to bring better dosing methods to the ward, meaning we aim not only to make pharmacometric model-based calculations useable by clinicians, but to actually get them to use it. We want doses to be determined by the best possible method, meaning real patients receiving doses that were determined (at least […]

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Antibiotic Dosing Calculator in Neonates and Children Trial

Research question: Does the dosing regimen (dose and dose interval) proposed by the dose calculator result in serum concentrations closer to the target concentration than the dose regimen achieved by currently used protocols? Background: A dosing calculator has been developed based on a pharmacokinetic analysis of vancomycin (532 subjects, 1676 concentrations), amikacin (682 subjects, 1717 […]

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What is needed for a dosing calculator?

Background: Once daily dosing of aminoglycosides is popular because these drugs have a concentration-dependent bactericidal spectrum and nephrotoxicity is related to a saturable uptake by the proximal renal tubules. High peak concentrations and low trough concentrations are consequently desirable. Current dosing of both aminoglycosides and glycopeptides for children in intensive care is protocol driven. Dosing in […]

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Online dose calculation tool for determining dosing regimens in the very young

Few tools are available to quickly calculate dose in neonates. A dosing calculator has been developed using age, weight and renal function. The aim of this calculator is to provide quick and accurate predictions of average steady state concentration (Csspred) and expected time course for a range of dosing regimens in neonates. The dosing calculator […]

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Pharmacokinetics of Tramadol in Human Neonates, Children and Adults and in Adult Rats, Cats, Dogs, Goats and Horses

Objective: To describe human maturation and between species differences in tramadol disposition. Background: (+)-Tramadol (tramadol) and its phase I metabolite (+)-O-desmethyltramadol (M1) are weak µ-opioid receptor agonists that are structurally related to morphine. The O-demethylation of tramadol to M1, the main analgesic metabolite, is catalysed by CYP2D6. CYP2D6 polymorphisms have been shown to influence M1 production and […]

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