Pharmacology dose calculations

It is common to find a pharmacist as a member of the hospital cardiopulmonary resuscitation (CPR) team, which responds to emergent situations that may require immediate patient care. These scenarios usually involve a patient who suddenly becomes nonresponsive, ceases spontaneous respirations, and/or experiences a life-threatening cardiac arrhythmia. The CPR team responds to such patients by implementing advanced cardiac life support (ACLS), which involves quick provision of an airway and electrical (defibrillation) and/or pharmacologic interventions to sustain cardiac function. The pharmacist s role on such a team involves the preparation of intravenous infusions needed in an emergent situation, dose calculations, and consultation regarding appropriate medication use. 

Ideal for studying the dose-response relationship for QT interval prolongation taking into account all the pharmacological properties of a compound The dog model is one of the most widely used anesthetized rabbits (especially female rabbits) have also been proposed for high sensitivity It provides complementary information with respect to in vitro tests (activity of metabolites, measurement of plasma drug concentrations, calculation of the volume of distribution) Possibility to induce experimental TdP... 

These values are obtained from in vitro enzyme experiments. From the previous relahonship between in vitro pharmacology measurements and free drug concentra-hons and those outHned here, it is reasonable to assume that cHnical dose size can be calculated from simple in vitro measurements. 

The pediatrician calculates the dose based on the infant s weight, choosing the infant dose recommended in a pediatric pharmacology reference text. He prescribes a maintenance dose, given q.i.d. by mouth prior to scheduled feedings, and advises the... 

Simple mathematical calculations by the first pharmacologists in the 1930s indicated that structurally specific drugs exert their action in very small doses and do not act on all molecules of the body but only on certain ones, those that constitute the drug receptors. For example, Clark [407] calculated that ouabain applied to the cells of the heart ventricle, isolated from the toad, would cover only 2.5% of the cellular surface. These observations prompted Clark [407,408] to apply the mathematical approaches used in enzyme kinetics to the effects of chemicals on tissues, and this formed the basis of the occupancy theory for drug-receptor interaction. Thus, pharmacological receptor models preceded accurate knowledge of receptors by many years. 

Male Sprague-Dawley rats weighing 180-240 g are fed a commercial laboratory with low concentrations of thyroid hormones, containing constant amount of unlabelled iodine. The animals are treated for at least seven days with the test compound to be evaluated, at a pharmacologically active dose determined by a previous biological studies. On the morning of the test day, rats are injected with a test dose of 131-1 (intravenously or intraperitoneally), and the concentration of radioactivity in the thyroid glands is measured after 1 1 hours. The blood concentration of 131-1 at these time points is measured, and the tissue to blood ratios are calculated for individual animals. 

Evaluate in vivo dose-response range, including dose-response comparison of lead candidates calculation of pharmacologically active doses, e.g., ED50 or ED)0 and therapeutic ratio when combined with no effect or minimum toxic effect dose level. 

New England Journal of Medicine 338 1128-1137 Pirmohamed M 2001 Pharmacogenetics and pharmacogenomics. British Journal of Clinical Pharmacology 54 345-357 Report 1997 Medication for older people. Royal College of Physicians, London Rolf S, Harper N J N 1995 Ability of hospital doctors to calculate drug doses. British Medical Journal 310 1173... 

The most widely used technique for the evaluation of hERG channel interaction is the voltage clamp. A detailed description of the experimental setup has been described elsewhere [119]. The hERG interaction is measured and reported as the % inhibition of the hERG current compared to the vehicle control at various concentrations of the NCE. The concentration that inhibits 50% (IC50) is calculated, whenever possible. The concentrations of NCE used in the assay are carefully selected based on the expected maximum plasma concentration (Cmax) at the pharmacologically active dose (usually based on studies in animal models) and the human plasma protein binding for the NCE. 

---