Pavan Vajjah

  • School of Pharmacy, University of Otago

Author Archive | Pavan Vajjah

Generalisation of T-optimality for discriminating between competing models – an application to paracetamol overdose

Background and objectives: The T-optimality criterion for model discrimination was introduced by Atkinson and Fedorov [1]. Application of this method required the condition that one of the competing models is correct. We term this criterion local T-optimality. In addition, T-optimal designs are generally not efficient for parameter estimation. The aims of current work are (1) to […]

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Pharmacodynamics of venlafaxine in overdose

Background: Venlafaxine, a serotonin-noradrenalin reuptake inhibitor, appears to be more toxic in overdose than other newer antidepressants. Various studies have shown that there is an increased risk of seizures [1], a potential for cardiac toxicity [2] and a higher rate of fatalities [3] with venlafaxine overdose when compared to other antidepressants. A population pharmacokinetic (PK) analysis […]

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Novel diagnostics for assessing fit of logistic regression models

Background: Assessment of goodness of fit of a model to the data set is essential to ensure the model provides a reasonable description of the events seen. For logistic regression the most common diagnostic used for this purpose is binning the data and comparing the empirical probability of an event in each bin to the model […]

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What to do about missing dosage history?

Background: An inaccurate or missing dose history (MDH) is one of the major obstacles in determining unbiased estimates of the pharmacokinetic (PK) parameters of a drug in clinical practice.  This is particularly the case with drug overdose when the patient may either not recall the events or choose not to provide an accurate history. Methods have […]

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