Principles of Biomedical Technology (Principles of Biomedical Science)

Unit 3: Unit 3.2 Emergency ResponsePBS 3.2Handling, Preparation, Storage and Disposal

Explain Drug Metabolism

Apply emergency or public-health rules to explain drug metabolism.

Builds on (2 levels back)inferred · high confidence

Read a protocol: Emergency decisions must follow the stated rule in order.
Balance benefit and risk: Interventions should help while minimizing harm.

Prerequisites are inferred: pending teacher review.

Re-learn the skill with worked practice and clear examples.

The liver metabolizes a drug, meaning it chemically changes the drug, often into a form the kidneys can remove.

Step 1: Spot the metabolizing organ

The liver is the main site of drug metabolism. It uses enzymes to change the drug's chemical structure.

Step	What happens	Where
Absorb	drug enters the blood	gut
Distribute	drug travels to tissues	bloodstream
Metabolize	drug is chemically changed	liver
Excrete	drug leaves the body	kidneys

Step 2: Know what 'change' means

Metabolism does not just move the drug; it turns it into a different chemical (a metabolite).

Step 3: Connect to excretion

After the liver changes the drug, the kidneys excrete it. Change comes before removal.

Practice

Using the table, which organ chemically changes a drug into a new form?

Reviewed

Step	What happens	Where
Absorb	drug enters the blood	gut
Distribute	drug travels to tissues	bloodstream
Metabolize	drug is chemically changed	liver
Excrete	drug leaves the body	kidneys

A.Liver
B.Gut
C.Bloodstream
D.Kidneys

Show the worked solution ▾

Answer: A. Liver

Step 1: Find the 'Metabolize' row: Metabolize is the chemical-change step.
Step 2: Read its 'Where' column: The Metabolize row lists the liver.

Why it's right: The Metabolize row pairs 'drug is chemically changed' with the liver, so the liver does the chemical change.

Why the others miss:

B: The gut is where the drug is absorbed, not chemically changed.
C: The bloodstream distributes the drug but does not change it.
D: The kidneys excrete the drug after it is changed; they do not metabolize it.

Aligned to Handling, Preparation, Storage and Disposal · reading level ~grade 9

Where you'd see this

A nurse explains to a patient that the liver breaks the medicine down, so liver problems can change the dose.

Careers that use this

Pharmacist: Explains how the liver breaks a drug down so a dose lasts the right amount of time.Clinical Pharmacologist: Studies first-pass metabolism to set safe drug doses.

Video library

Watch: Explain Drug Metabolism

Pharmacokinetics: How Drugs Move Through the Body

Professor Dave Explains · 7:55

Guided notes

Fill these in as you work through the lesson.

Big idea: The body handles a drug in four steps (ADME); the liver metabolizes the drug, chemically changing it before the kidneys remove it.

Key terms: write the meaning

ADME (absorb, distribute, metabolize, excrete):
Metabolize (chemically change the drug):
Liver (main organ that metabolizes drugs):
First-pass (liver changes a swallowed drug before it reaches the body):

The rule

In ADME, the step chemically changes the drug, and it mostly happens in the .

Check yourself

What do the four letters in ADME stand for?
Which ADME step means the drug is chemically changed?
Why might a swallowed dose need to be larger than an injected dose?

Work one example

Trace ibuprofen through ADME: absorbed in the gut, distributed by the blood, metabolized (changed) by the liver, then excreted by the kidneys. Name the step that changes the drug.