Pharmacokinetic and pharmacodynamic Assignment Example | Topics and Well Written Essays - 750 words

Pharmacokinetic and pharmacodynamic - Assignment Example According to Birkett (2005), response parameters measures in an organism involve aspects like blood pressure, concentration of hormones produced by the drug or severity of side effects. The first point when the curve diverts from the zero scale represents the threshold drug dosage. At this concentration, the drug starts exhibiting desired response from the organism. As concentration increases, the graph gets steeper. This means the levels of response increases together with severity of a drug’s side effects. At extremely high dosage, the curve grows almost flat again meaning adverse biological response and even fatality. Technically, drug response time may delay, causing a wrong response to be measured and plotted in a exposure-response graph. Delay in response is caused by the effect of drug distribution and re-distribution around the body system. When data from such unconventional measurements are plotted, they give either clockwise or anticlockwise hysteresis loops. In pharmacokinetics, hysteresis loops signifies presence of delayed response with changing drug concentration. At times, the hysteresis loop can assume a clockwise direction. An anticlockwise hysteresis loop usually results from the differing responses associated with distribution and re-distribution of the drug’s active components to site of action. On the contrary, a clockwise hysteresis loop occurs when there is rapid tolerance whereby after the first administration, tolerance develops which makes similar drug concentrations to cause different responses. After tolerance is developed, a succeeding dosage of similar concentration causes a greater effect than the first level of concentration. As acknowledged earlier, hysteresis in food or drug compounds results from differing responses associated with similar level of substance concentration. Hysteresis occurs when there is either tolerance of the substance or as an effect of substance distribution properties. Numerous