Pharmacology

Metabolized drugs are then excreted from the body, primarily through urine or feces. The video provides a quick review of the entire drug journey: administration, absorption, distribution, metabolism, and excretion.

The video begins by introducing pharmacodynamics, which is the study of how drugs affect the body. It explains that drugs work like keys fitting into specific receptors on cells to either stimulate or inhibit actions, using antihistamines as an example of blocking receptors to stop allergic reactions.

Drugs can act as agonists, producing a predicted action when binding to receptors, or as antagonists, blocking receptors to prevent other chemicals from attaching. Some drugs, like diphenhydramine, can interact with multiple receptor types, leading to side effects like drowsiness.

Pharmacokinetics describes the journey of drugs within the body, encompassing four stages: absorption, distribution, metabolism, and excretion. Absorption involves the drug entering the bloodstream from its administration site.

After absorption, drugs are distributed to various tissues and organs via the bloodstream. The liver plays a crucial role in drug metabolism, breaking down drugs into active or inactive compounds to prevent toxicity.

Drug effects depend on the amount administered and the time it stays in the body. The dose-response curve illustrates how a patient's response relates to the drug amount, showing no effect, increasing effect, and maximum effect ranges. The time-response curve shows how drug effects change over time.

The therapeutic window is the range between the minimum effective concentration for desired effects and the minimum for adverse effects. Proper drug scheduling ensures the drug stays within this window, maximizing effectiveness, minimizing side effects, and reducing drug interactions.