Pharmacodynamics drug interactions affecting

Pharmacokinetic drug interactions occur where one drug affects the absorption, distribution, metabolism or excretion of the other. Pharmacokinetic drug interactions are harder to predict than pharmacodynamic drug interactions and in many cases, affect different patients differently. 

Apart from patient-specific parameters, external factors - most importantly the concomitant uptake of certain other chemicals present in diet, environment and especially other drugs - influence drug actions. Possible effects are manifold and can affect all stages of pharmacokinetic and pharmacodynamic processes in the body. Also direct interaction and inactivation of concomitantly administered substances are possible. Drug-drug interactions via modulation of metabolism present a very hot topic in pharmaceutical research and drug design. 

Factors That Affect Compliance Side Effects, Risk-Benefit Ratio, Drug-Drug Interactions, Pharmacokinetic or Pharmacodynamic Effects, Cost, and Preferences... 

Although when related to a dose the clinical outcome of a drug interaction may appear the same, it is useful to distinguish between pharmacokinetic and pharmacodynamic causes of the interaction. In the former case, the change in response is caused by a change in the concentration of the affected dmg, together perhaps with one or more metabolites. In the latter, there may be no change in pharmacokinetics at all. 

Drug interactions occur when the presence of one drug affects the activity of another. This may occur either because both drugs act through the same pathway(s) - these are called pharmacodynamic interactions - or through effects on absorption, distribution, metabolism or excretion - pharmacokinetic interactions. The result may be an adverse reaction or modified effectiveness. Some specific examples are given below ... 

Pharmacology may be described as the study of the properties of drugs and how they interact with/affect the body. Within this broad discipline exist (somewhat artificial) subdisciplines, including pharmacokinetics and pharmacodynamics. 

Shape and stereochemical. These properties affect the pharmacodynamic phase of drug action and influence the drug s interaction with its target receptor. Shape and stereochemical properties describe the structural arrangement of the drug molecule s constituent atoms and influence the molecule s final approach toward the target receptor. 

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