Core - Pharmacokinetics and Pharmacodynamics

Chapter 6

Pharmacokinetics: Drug Excretion and Clearance

6.1 : Drug Elimination: Overview

6.1 : Drug Elimination: Overview

When drugs enter the body, they eventually undergo irreversible elimination. Drug elimination primarily involves excretion and metabolism or ...

6.2 : Elimination Kinetics: First-Order and Zero-Order

6.2 : Elimination Kinetics: First-Order and Zero-Order

Eliminating drugs from the body is a vital process that occurs through excretion or metabolism. Understanding the kinetics of drug elimination is crucial ...

6.3 : Renal Drug Excretion: Overview

6.3 : Renal Drug Excretion: Overview

The kidneys are primary excretory organs, filtering waste products from the bloodstream and excreting them into urine. The kidneys efficiently eliminate ...

6.4 : Renal Drug Excretion: Glomerular Filtration

6.4 : Renal Drug Excretion: Glomerular Filtration

The kidney serves as the primary organ responsible for eliminating drugs and their metabolites from the body. This process, known as renal elimination, ...

6.5 : Renal Drug Excretion: Tubular Reabsorption

6.5 : Renal Drug Excretion: Tubular Reabsorption

After glomerular filtration, substances in the tubular lumen transport back into the bloodstream via tubular reabsorption. Nutrients are actively ...

6.6 : Renal Drug Excretion: Tubular Secretion

6.6 : Renal Drug Excretion: Tubular Secretion

Blood exits glomeruli via efferent arterioles, reaching the capillary plexus surrounding the proximal tubule. Here, unfiltered drugs are secreted into the ...

6.7 : Renal Drug Excretion: Effect of Urine pH, Flow Rate, and Drug p<em>K</em>a

6.7 : Renal Drug Excretion: Effect of Urine pH, Flow Rate, and Drug pKa

Urine pH and a drug's pKa determine its percentage ionization, which influences renal reabsorption and elimination. Urine pH depends on diet, drug ...

6.8 : Hepatic Drug Excretion: Enterohepatic Cycling

6.8 : Hepatic Drug Excretion: Enterohepatic Cycling

The hepatic biliary system expels drugs and metabolites via bile secretions. Hepatocytes lining bile canaliculi produce bile that contains water, ...

6.9 : Hepatic Drug Excretion: Influencing Factors

6.9 : Hepatic Drug Excretion: Influencing Factors

Bile, produced by hepatocytes, primarily comprises water, bile salts, and pigments. Membrane transporters in hepatocytes transfer the drug into bile. ...

6.10 : Drug Excretion: Pulmonary and Glandular Routes

6.10 : Drug Excretion: Pulmonary and Glandular Routes

Drugs are excreted through various unconventional routes, including the lungs, breast milk, and saliva. In the lungs, volatile drugs diffuse into the ...

6.11 : Drug Excretion: Miscellaneous Routes

6.11 : Drug Excretion: Miscellaneous Routes

Various bodily processes, including sweating, tears, and the digestive system, contribute to drug excretion. Nonionized lipophilic drugs passively diffuse ...

6.12 : Drug Clearance: Overview

6.12 : Drug Clearance: Overview

A drug that enters the body gets eliminated by the kidneys and liver through urine or bile, respectively. A pharmacokinetic parameter, drug clearance, ...

6.13 : Clearance Models: Physiological Models

6.13 : Clearance Models: Physiological Models

Drug clearance features irreversible drug removal from any organ in the body. Physiological models determine clearance through an individual organ, ...

6.14 : Clearance Models: Compartment Models

6.14 : Clearance Models: Compartment Models

Clearance directly measures drug elimination from the central compartment, which comprises plasma and highly perfused organs like kidneys and liver. ...

6.15 : Clearance Models: Noncompartmental Models

6.15 : Clearance Models: Noncompartmental Models

Typically, clearance describes the drug elimination from the body using compartment models. An alternative, the noncompartmental approach, estimates ...

6.16 : Renal Drug Clearance: Overview

6.16 : Renal Drug Clearance: Overview

Renal clearance is defined as a constant fraction of the central volume of distribution containing the drug excreted by the kidney per unit of time. It is ...

6.17 : Renal Drug Clearance: Comparison Between Renal Excretion Methods

6.17 : Renal Drug Clearance: Comparison Between Renal Excretion Methods

Renal clearance is the summation of kidney filtration, secretion, and reabsorption calculated by a specific equation. It is typically associated with the ...

6.18 : Factors Affecting Renal Clearance: Drug's Physicochemical Properties and Plasma Levels

6.18 : Factors Affecting Renal Clearance: Drug's Physicochemical Properties and Plasma Levels

Various factors impact a drug's renal clearance, including its physical-chemical properties and plasma levels. Molecular size, lipid solubility, and ...

6.19 : Factors Affecting Renal Clearance: Drug Distribution and Drug Interactions

6.19 : Factors Affecting Renal Clearance: Drug Distribution and Drug Interactions

Renal clearance, pivotal in drug elimination, can be affected by drug distribution and interactions. Drugs with a large distribution volume or bound to ...

6.20 : Factors Affecting Renal Clearance: Renal Impairment

6.20 : Factors Affecting Renal Clearance: Renal Impairment

Renal dysfunction significantly impairs renal drug clearance. Renal failure can be caused by various factors. Uremia, characterized by impaired glomerular ...

6.21 : Renal Failure: Dose Adjustments

6.21 : Renal Failure: Dose Adjustments

In patients with renal impairment, drugs exhibit altered pharmacokinetics. Reduced renal clearance and elimination rate result in prolonged elimination ...

6.22 : Determination of Renal Drug Clearance: Graphical and Midpoint Methods

6.22 : Determination of Renal Drug Clearance: Graphical and Midpoint Methods

Renal clearance can be determined using graphical and midpoint methods. In the graphical method, clearance can be calculated and obtained by plotting the ...

6.23 : Hepatic Drug Clearance: Restrictive and Nonrestrictive Clearance

6.23 : Hepatic Drug Clearance: Restrictive and Nonrestrictive Clearance

Hepatic clearance is the volume of blood cleared of a drug by the liver per unit of time. It equals total body clearance minus renal clearance. Most ...

6.24 : Hepatic Drug Clearance: Effect of Protein Binding

6.24 : Hepatic Drug Clearance: Effect of Protein Binding

Hepatic clearance can be affected by protein binding based on the extraction ratio of the drug. Drugs with high extraction ratios are flow-limited and ...

6.25 : Hepatic Drug Clearance: Role of Transporters

6.25 : Hepatic Drug Clearance: Role of Transporters

In the liver's bile canaliculi, modification of influx and efflux transporters can influence intrinsic clearance. Transporters play a major role in ...

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