Integrated Pharmacology and Drug Clearance Flashcards
Drug elimination from the body is a process that includes both […] and […]
Metabolism
Excretion
How are filtered drugs (and honestly this same explanation applies to just general kidney function for all sustances, not just drugs) handled in the nephron?
They can be:
- Filtered
- Reabsorbed to plasma
- Excreted in urine
- Not filtered
- Secreted to be excreted in urine
- Not secreted to remain in plasma
What are the 2 ways drugs can be excreted?
Renal (urine) or biliary (stool)
True - changing the pH of the urine can change the properties of the drug and change whether it will be reabsorbed or remain in the urine
How does renal clearance affect the maintenance dosing rate of a drug?
As a refresher, what is first pass metabolism? Why is it so important in drug metabolism?
The clearance of drugs is reduced in what settings?
False
During WWII there was a shortage of penicillin. Probenecid was co-administered with penicillin. Why?
- What are thiazide diuretics?
- What do they treat?
- What is a potential side effect of taking them?
- Diurietics that compete with the OAT transporter for uric acid, reducing secretion of uric acid and resulting in increased uric acid in the blood
- They can treat HTN / edema
- Gouty arthritis
- If the renal clearance of the drug = GFR, then the drug is only […]
- If the renal clearance of the drug < GFR, then the drug is […] and […]
- If the renal clearance of the drug is > GFR, then the drug is […] and […]
What is clearance?
The best way to think of this is to look at the diagram and say “in 1 minute, the drug was removed from 15mL of plasma”. That helps make this definition make sense. The drug has been cleared from 15 mL of plasma in 1 minute.
A
B
What is probenecid?
What condition does it treat?
How?
What is the equation that defines elimination rate?
How is it related to the equation that defines clearance?
- What is biotransformation of a drug?
- What effect does biotransformation have on the drugs excretion?
Biotransformed drugs are less lipophilic, therefore they are less likely to remain in the plasma when they encounter the kidney. Many drugs are designed to be biotransformed to tag them for excretion, but some are biotransformed to the active form so we don’t want to excrete those. Therefore, it’s important that those drugs be designed such that the body reabsorbs them in the kidney.
