FIRST PASS METABOLISM for beginners

Summary

In this video, the host explains the concept of first-pass metabolism, emphasizing its significance in pharmacy practice. First-pass metabolism, or the first-pass effect, refers to the process where a drug is metabolized in the liver and other organs before reaching its site of action, often reducing its efficacy. The discussion highlights the impact of genetic polymorphism on enzyme levels, which affects how individuals metabolize drugs, as well as the influence of the route of administration on drug bioavailability. Additionally, the video clarifies the difference between regular drugs and prodrugs, which become active only after metabolism.

Takeaways

• 😀 First pass metabolism refers to the process where a drug is metabolized before reaching its site of action.
• 💊 This metabolism primarily occurs in the liver, but other organs like the GI tract and lungs can also play a role.
• 🔬 Genetic polymorphism affects drug metabolism, with individuals categorized as hyper metabolizers or poor metabolizers based on enzyme levels.
• 🌍 Ethnicity and nationality can influence the expression of different types of CYP enzymes, impacting drug efficacy.
• 📦 The route of administration significantly affects first pass metabolism, with oral drugs undergoing more metabolism than intravenous medications.
• 🚀 Intravenous medications bypass first pass metabolism, allowing them to reach the site of action more quickly.
• 📉 Oral medications typically have the least bioavailability due to extensive metabolism during first pass.
• ⚗️ Prodrugs are inactive until metabolized, leading to a higher concentration of the active drug after first pass metabolism.
• 🧬 Understanding first pass metabolism is crucial in clinical practice for optimizing drug dosing and effectiveness.
• 👍 The video aims to simplify complex concepts for better understanding and encourages viewer interaction through likes and comments.

Q & A

What is first-pass metabolism?

First-pass metabolism, also known as the first-pass effect, refers to the process where a drug is metabolized by the body before it reaches its site of action, typically occurring in the liver.

Why is first-pass metabolism significant in clinical practice?

It is significant because it results in a reduced amount of the active drug reaching the site of action, which can impact the effectiveness of the medication.

What organs are involved in the first-pass metabolism besides the liver?

Other organs involved in first-pass metabolism include the gastrointestinal (GI) tract and the lungs.

What is genetic polymorphism in the context of drug metabolism?

Genetic polymorphism refers to the presence of at least two variations of enzymes responsible for drug metabolism, leading to individuals being classified as hyper metabolizers or poor metabolizers.

How does route of administration affect drug metabolism?

The route of administration influences how much of the drug is metabolized before reaching the site of action; for instance, oral drugs undergo significant first-pass metabolism, whereas intravenous drugs bypass this process.

What is the order of routes of administration based on bioavailability?

The order from highest to lowest bioavailability is intravenous, transdermal, injectable, suppositories, and oral medications.

What are prodrugs, and how do they relate to first-pass metabolism?

Prodrugs are inactive compounds that become active only after undergoing metabolism. Unlike regular drugs, they can increase the concentration of the active drug following first-pass metabolism.

What impact does ethnicity have on enzyme expression related to drug metabolism?

Ethnicity can influence the expression of specific cytochrome P450 (CYP) enzymes, leading to variations in drug metabolism among different populations.

What can be the consequences of being a poor metabolizer?

Poor metabolizers may experience reduced efficacy of medications or increased risk of side effects, as the drug concentration may remain too high in the body.

What did the speaker hope to achieve by breaking down the topic of first-pass metabolism?

The speaker aimed to simplify the complex topic of first-pass metabolism for better understanding, hoping viewers found the content helpful.