Metabolism and excretion: the liver and kidneys
Explains the 'big problem' the liver solves: kidneys can't hold onto lipid-soluble drugs until metabolism makes them water-soluble.
Where this fitsConnects to 1 · Unlocks 2
- Connects to
- ADME: the drug's journey through the body — This zooms into M and E.
- Unlocks
- When enzymes change: induction, inhibition and genetics — Enzyme levels change — induction, inhibition, genetics.
- First-pass metabolism and prodrugs — Oral drugs meet the liver before the brain.
Walk through
The kidneys' problem
Kidneys filter blood and collect waste in the bladder, but lipid-soluble drugs diffuse back into circulation before excretion.
Analogy and worked example
Analogy: Taking out the trash in a rainstorm: greasy bags (lipid-soluble drugs) slide right back out of the bin. The liver ties handles on them (Phase I) and puts them in a heavy bag (Phase II), so they stay in the bin until collection.
Why is it dangerous that 'the dose makes the poison'?
- Toxicity always depends on dose — any chemical can be toxic at a high enough dose.
Tip: the ← and → keys move through the lesson.
Full lesson: Enzymes and phases of metabolism · Excretion and the kidney-liver connection