Pharmacodynamics is the term utilized to define the effect that a drug has on the body. It controls whether the drug is going to be actual in the treatment of disease with the minimum of side-effects. The initial step leading to a drug response is the binding of a drug to its receptor. This drug receptor interaction is followed by a sequence of intracellular events that results in the response of the cell to the drug.
Pharmacokinetics is the term is used to label the effect the body, its organs and tissues has on the action of a drug once it is administered. It is uncommon for the same amount of drug to be eventually available at its site of action. As soon as the drug arrives the body, the body will perform on the drug to change its concentration as well as in many cases its chemical structure. In order to be able to custom drugs wisely as well as at the appropriate doses we need to understand the pharmacokinetics of the drug. To exert an effect on the body a drug must spread its target tissue in a suitable form as well as in sufficient concentration to pledge a specific therapeutic effect. Once the pharmacokinetics of a drug are recognised it is then possible to determine:
• the amounts (concentrations) to be given to the patient
• the most operative route of administration
• How often the dose has to be given in order to obtain maximum therapeutic benefit for the patient.
The unique characteristics of all patient can influence both the pharmacokinetics and pharmacodynamics processes involved in the drug action. They can likewise determine the patient's response. Sources of individual variation include:
• interactions among drugs if the patient is receiving more than one drug at the same time
• physiological variables such as age sex and weight
• patho-physiological variables related to disease (especially abridged function of the kidney and liver, which are the major organs of drug elimination)
• Genetic variables which can alter the metabolism of drugs as well as predispose the patient to unique side-effects which cannot be predicted.
When we consider each of the possible uncontrolled variables associated with the treatment of an individual patient - such as the patient's disease as well as the multiple pharmacological effects of many drugs - it is easy to consider that any attempt at rational drug therapy is impossible. To the inexperienced as well as untrained student initial encounters with drug treatment may appear as the best guess on the part of the clinical team backed up by years of clinical experience of what drugs have worked in the past on patients with an alike illness. Luckily this is not true. Of all branches of practical medicine it is maybe the therapeutic aspect of patient care with drugs which is most agreeable to objective research. For ex we can:
• interfere in the patient's disease with a drug
• accurately measure the response to the drug
• Use the data attained from one group of patients to develop and inform good practice for the use of the drug in other patients.
When we administer a medicine to an enduring the active drug itself is only one variable in a complex pattern of events that will determine how that individual patient responds. It is significant, therefore that we devote time considering all of the factors that may happen to our therapeutic objective between the writing of the prescription as well as the patient's final response to the drug.
Using the above information besides information from your own sources, describe the difference among Pharmacodynamics and Pharmacokinetics in detail