Pharmacodynamics is the study of the molecular effects of a drug within the body. These molecular effects include interactions with receptors sites that react with certain chemicals to cause a desirable or undesirable effect within a cell. Understanding pharmacodynamics allows for one to consider the concentration of a drug needed to produce a therapeutic response at the target site that can contribute to factors that relate to dosage, dosage form, and frequency of the dosage (Smith, 2016). Pharmacokinetics is the study of how a drug moves through the body. The defining principles of this process include absorption, distribution, metabolism, and excretion of a drug. Understanding this process allows one to measure the onset of drug action, …show more content…
It is an undesirable pharmacologic effect of that drug that is not triggered by the immune system. Usually, the adverse effect is intolerable, and the patient has to stop taking the medication (Smith, 2016). For example, the antipsychotic drug haloperidol can cause neuroleptic malignant syndrome which is life-threating and an allergic reaction would not produce this syndrome. Furthermore, a medication intolerance can produce similar symptoms of an allergic reaction (e.g. rash)(Smith, …show more content…
The five Pregnancy Categories were developed to indicate a drug’s potential or actual teratogenic effects and are used as guidelines for drug therapy in pregnant women. Category A indicates a drug having relatively no risk to the embryo or fetus. An example would be folic acid used to help prevent neural tube defects. Drugs labeled as Category D or X has significant evidence indicating these drugs do cause teratogenicity. An example of this type of teratogenic medication would be Accutane used to treat acne (Smith,