Pharmacokinetics Absorption, Distribution, Metabolism, Excretion | Made Easy

Summary

This video provides a clear and engaging overview of pharmacokinetics, explaining what happens to medications after they enter the body. Using the mnemonic 'ADME,' it covers Absorption (how medications enter the body), Distribution (how they spread via the bloodstream), Metabolism (how the liver and other organs process drugs), and Elimination (how medications are excreted, primarily by the kidneys). Key concepts like first-pass metabolism, half-life, nephrotoxicity, and the impact of age or organ dysfunction on drug handling are highlighted. The video uses practical examples, clinical relevance, and memorable tips to simplify complex pharmacology concepts for nursing students and healthcare learners.

Takeaways

• 💊 Pharmacokinetics studies what happens to medications after they enter the body, summarized by ADMEs: Absorption, Distribution, Metabolism, and Elimination.
• 🧪 Absorption refers to how a medication enters the bloodstream and depends on the route of administration (oral, injection, inhalation, transdermal, rectal, sublingual).
• 🩸 Distribution describes how medications travel throughout the body via the bloodstream and may bind to specific sites, like opioids binding to pain receptors.
• ⚡ Certain medications, like opioids, can affect vital signs by lowering heart rate, blood pressure, and respiratory rate.
• 🏭 Metabolism is how the body processes drugs, primarily in the liver, converting them into active or inactive metabolites.
• 🌟 First-pass phenomenon occurs when orally taken medications pass through the liver before reaching systemic circulation, affecting drug efficacy.
• 👶 Newborns have underdeveloped metabolic enzyme systems, making drug metabolism slower, while elderly clients have decreased enzymatic activity, increasing toxicity risk.
• 🚰 Elimination is the removal of medications from the body, primarily through the kidneys, with other minor routes including bowel and exocrine glands.
• ⏱️ Half-life measures how long it takes for half of a medication to be eliminated, guiding dosing schedules to maintain therapeutic levels.
• ⚠️ Nephrotoxicity refers to kidney damage caused by certain drugs, and impaired kidney function can significantly increase the risk of drug toxicity.
• 🩺 Factors like age, liver and kidney function, and route of administration critically influence how medications are absorbed, metabolized, distributed, and eliminated.

Q & A

What does pharmacokinetics study?

Pharmacokinetics studies what happens to medications after they enter the body, including how they are absorbed, distributed, metabolized, and eliminated.

What does the acronym A-D-M-E stand for in pharmacokinetics?

A-D-M-E stands for Absorption, Distribution, Metabolism, and Elimination.

What are the main routes of medication absorption?

Main routes include oral (PO), intravenous (IV), intramuscular (IM), subcutaneous (SQ), sublingual (SL), rectal (PR), inhalation, and transdermal (through the skin).

Why is IV administration considered the fastest route?

IV administration delivers medication directly into the bloodstream, allowing it to reach the entire body almost immediately.

How does the distribution of medication in the body occur?

Distribution occurs through the bloodstream, transporting medications to organs and tissues. Medications may also bind to specific receptor sites.

What is the first-pass phenomenon and which medications does it affect most?

The first-pass phenomenon occurs when orally administered medications pass through the liver before reaching systemic circulation, reducing the active drug available in the body.

How does liver disease or aging affect medication metabolism?

Liver disease reduces the ability to metabolize drugs, increasing the risk of toxicity. Similarly, elderly individuals have decreased enzymatic activity, slowing metabolism.

What is the primary organ responsible for drug elimination, and why is kidney function important?

The kidneys are the main organ responsible for eliminating medications. Impaired kidney function or age-related decline can lead to higher drug levels and increased risk of toxicity.

What is a drug's half-life and why is it clinically important?

Half-life is the time it takes for half of a medication to be eliminated from the blood. It guides dosing schedules to maintain therapeutic levels and prevent toxicity.

What does nephrotoxicity mean and which medications can cause it?

Nephrotoxicity refers to kidney damage caused by certain medications. Examples include antibiotics like gentamicin, which can be harmful to the kidneys if not monitored.

How does age affect the metabolism and elimination of medications?

Newborns have underdeveloped metabolic enzyme systems, making medication metabolism difficult. Elderly individuals have decreased enzymatic activity and kidney function, leading to slower metabolism and elimination, increasing toxicity risk.

Give examples of medications administered via inhalation and transdermal routes.

Inhalation: albuterol and steroids for asthma or COPD. Transdermal: nitroglycerin patches, nicotine patches, fentanyl patches.