Absorption Process Visualized and Simplified

Summary

This video explains the journey of a medication taken by mouth, detailing how it travels through the gastrointestinal (GI) tract and gets absorbed into the bloodstream. Starting with ingestion, the video explores the roles of solubility, medication coatings, and digestion in the stomach. The majority of absorption happens in the small intestine, where the medication enters the bloodstream through passive, facilitated, or active diffusion. Afterward, the drug passes through the liver, where first-pass metabolism may reduce its bioavailability. Finally, the medication circulates through the body, reaching its target cells to perform its intended action.

Takeaways

• 😀 After ingesting medication, it travels down the esophagus to the stomach.
• 😀 Solubility of the medication affects how quickly it is absorbed in the small intestines.
• 😀 The stomach plays a role in digesting and breaking down the medication before absorption.
• 😀 Coatings on medications can delay breakdown in the stomach to prevent irritation or modify release time.
• 😀 Enteric-coated aspirin is an example of a medication designed to avoid stomach irritation.
• 😀 The majority of medication absorption occurs in the small intestine after it reaches solution.
• 😀 Medications are absorbed into the hepatic vein from the small intestine and travel to the liver.
• 😀 Absorption into the bloodstream can occur through passive diffusion, facilitated diffusion, or active transport, depending on the medication.
• 😀 The liver processes the medication, and the first-pass metabolism can significantly reduce the drug's bioavailability.
• 😀 Once processed, the medication enters the bloodstream, is carried by the heart, and reaches its target cells, where it exerts its effects.

Q & A

What happens to a medication after it is ingested?

After ingestion, the medication travels down the esophagus and into the stomach, where it begins to dissolve and get broken down. It then moves into the small intestine, where the majority of absorption occurs.

How does solubility affect the absorption of a medication?

Solubility affects how quickly a medication dissolves in the stomach, which in turn influences how fast it can be absorbed once it reaches the small intestine. Medications that dissolve more easily tend to be absorbed faster.

What role does the coating of a medication play?

The coating of a medication can serve several purposes, such as delaying the breakdown in the stomach to prevent irritation or controlling when the medication is released, such as in delayed-release tablets.

What is an example of a medication with a special coating, and what is its purpose?

Enteric-coated aspirin is a good example. Its coating delays the breakdown in the stomach to prevent gastrointestinal irritation.

Where does the majority of absorption of medications occur?

The majority of absorption happens in the small intestine, once the medication has dissolved and is in solution.

How does a medication enter the bloodstream after absorption in the small intestine?

After absorption in the small intestine, the medication enters the hepatic portal vein, then travels to the liver, where it can undergo metabolism before entering the bloodstream.

What are the main mechanisms by which medications are absorbed into the bloodstream?

Medications can be absorbed through passive diffusion, facilitated diffusion, or active transport. Passive diffusion occurs without energy, facilitated diffusion requires proteins on the cell membrane, and active transport requires energy to move the medication.

What is first-pass metabolism and how does it affect drug bioavailability?

First-pass metabolism refers to the process where a medication is metabolized in the liver before it reaches the rest of the body. This can reduce the bioavailability of the drug, meaning less of the drug enters the bloodstream in its active form.

How much of a drug might be lost during first-pass metabolism?

During first-pass metabolism, a drug can lose a significant portion of its potency. For example, if a person takes 100% of a medication, only 70% may remain after passing through the liver.

How does a drug reach its site of action after entering the bloodstream?

Once in the bloodstream, the drug is carried to various parts of the body, where it crosses from the blood vessels into the interstitial fluid and enters the cells to exert its effects.