Pharmacology: Drug Elimination & Kidney Function

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which process primarily removes intact drugs from the body?

Excretion (correct)

Absorption

Distribution

Biotransformation

What is the primary organ responsible for renal drug excretion?

Intestines

Liver

Kidneys (correct)

Lungs

Which type of nephron is characterized by long loops of Henle that extend into the medulla?

Juxtamedullary nephrons (correct)

Cortical nephrons

Medullary nephrons

Superficial nephrons

How is drug clearance typically expressed?

Volume of fluid removed per unit time Signup and view all the answers

What is the role of the glomerulus in the nephron?

Filtration of blood Signup and view all the answers

Volatile drugs, such as gaseous anesthetics, are mainly excreted through which route?

Expired air Signup and view all the answers

Which component is NOT involved in drug elimination?

Absorption Signup and view all the answers

What maintains the normal fluid volume and electrolyte composition in the body?

Kidney function Signup and view all the answers

Which statement about renal excretion is correct?

It primarily eliminates nonvolatile and polar drugs. Signup and view all the answers

The structure of the kidney where filtration begins is called what?

Glomerulus Signup and view all the answers

What does the hepatic duct do?

Joins with the cystic duct to form the common bile duct. Signup and view all the answers

Which components primarily make up bile?

Water, bile salts, and bile pigments. Signup and view all the answers

What is enterohepatic circulation?

The reabsorption and excretion process of drugs through bile. Signup and view all the answers

What happens when drugs that undergo enterohepatic circulation are administered?

They can generate multiple peaks in the plasma drug concentration curve. Signup and view all the answers

What characteristic must a drug have for primary excretion via bile?

Molecular weights above 500. Signup and view all the answers

When is it difficult to determine if a drug in feces is due to biliary excretion?

After oral administration. Signup and view all the answers

What can saturate the process of drug secretion into bile?

High drug concentrations. Signup and view all the answers

After a drug is administered parenterally, finding it in feces suggests what?

Some of the drug was excreted in bile. Signup and view all the answers

What is a notable feature of drugs in enterohepatic circulation?

They can experience a change in plasma concentration levels. Signup and view all the answers

Which cellular structures are responsible for the production of bile?

Hepatic cells. Signup and view all the answers

Which of the following factors primarily influences glomerular filtration?

Hydrostatic pressure within the glomerular capillaries Signup and view all the answers

What is a characteristic of active tubular secretion?

It is limited by the capacity of the carrier system Signup and view all the answers

Which of the following statements about drug protein binding is correct?

It has little effect on the elimination half-life of drugs primarily secreted by active secretion. Signup and view all the answers

Renal excretion of drugs may occur through which process?

A combination of glomerular filtration, active tubular secretion, and tubular reabsorption Signup and view all the answers

How does the free drug concentration in plasma influence renal clearance?

Increases proportionately leading to enhanced renal clearance. Signup and view all the answers

Which drugs are eliminated primarily through renal excretion?

Nonvolatile, water soluble, and low molecular weight drugs Signup and view all the answers

What occurs during tubular reabsorption?

Filtered drugs are reabsorbed back into the plasma, which can be active or passive. Signup and view all the answers

What defines the process of glomerular filtration?

It filters drugs based on their size and charge. Signup and view all the answers

Which statement about renal blood flow is true?

Approximately 25% of cardiac output is received by the kidneys. Signup and view all the answers

Study Notes

Drug Elimination and Clearance

Drug elimination is categorized into excretion and biotransformation
Drug excretion is the removal of the intact drug
Most nonvolatile and polar drugs are excreted through kidneys into urine
Other excretion pathways include bile, sweat, saliva, milk, and lungs (for volatile drugs)

Kidney Anatomy and Physiology

Kidneys are the primary excretory organs, removing metabolic waste and maintaining fluid and electrolyte balance
Kidneys have a cortex and medulla
Nephrons are the basic functional units of kidneys, responsible for waste removal and balance
Cortical nephrons have short loops of Henle, while juxtamedullary nephrons have longer loops extending into the medulla
Longer loops concentrate urine more effectively due to greater reabsorption capacity

Renal Drug Excretion

Renal excretion is a significant elimination route for many drugs
Drugs are excreted through glomerular filtration, active tubular secretion, and tubular reabsorption
Glomerular filtration primarily removes small, free drugs
Active secretion is a carrier-mediated process that moves drugs against concentration gradients. It is capacity-limited
Tubular reabsorption can be active or passive, returning substances to the blood.

Biliary Excretion

Biliary excretion is another route for drug elimination, mainly for drugs with high molecular weights
Anatomically, bile ducts transport bile made by hepatic cells and bile pigments from the liver through gallbladder and into the duodenum
Compounds that go through enterohepatic cycles show secondary peaks in the plasma-concentration curve - the drug is secreted into bile, passes through intestines, and then reabsorbed

Factors Influencing Excretion

Protein binding of drugs impacts glomerular filtration as only free drugs can be filtered
Drug ionization (pH of urine) affects tubular reabsorption

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the essential concepts of drug elimination and the role of kidneys in pharmacology. This quiz covers topics like drug excretion pathways, kidney anatomy, and the processes involved in renal drug excretion. Test your understanding of how kidneys regulate drug clearance from the body.