Chapter 6
Pharmacokinetics: Drug Excretion and Clearance
Eliminação de drogas: visão geral
When drugs enter the body, they eventually undergo irreversible elimination. Drug elimination primarily involves excretion and metabolism or ...
Cinética de eliminação: primeira ordem e ordem zero
A drug that enters the body is eliminated in due course, primarily via the kidneys.
Clearance is a pharmacokinetic parameter, relating a drug's ...
Excreção renal de drogas: visão geral
The kidneys are primary excretory organs, filtering waste products from the bloodstream and excreting them into urine.
The kidneys efficiently eliminate ...
Excreção renal de drogas: filtração glomerular
In kidneys, drugs enter the renal artery, pass through the afferent arterioles, and drain into the glomerular capillaries surrounded by the Bowman's ...
Excreção renal de drogas: reabsorção tubular
After glomerular filtration, substances in the tubular lumen transport back into the bloodstream via tubular reabsorption.
Nutrients are actively ...
Excreção renal de drogas: secreção tubular
Blood exits glomeruli via efferent arterioles, reaching the capillary plexus surrounding the proximal tubule.
Here, unfiltered drugs are secreted into the ...
Excreção renal de drogas: efeito do pH da urina, taxa de fluxo e drogas pKa
Urine pH and a drug's pKa determine its percentage ionization, which influences renal reabsorption and elimination.
Urine pH depends on diet, drug ...
Excreção hepática de drogas: ciclagem entero-hepática
The hepatic biliary system expels drugs and metabolites via bile secretions.
Hepatocytes lining bile canaliculi produce bile that contains water, ...
Excreção hepática de drogas: fatores de influência
Bile, produced by hepatocytes, primarily comprises water, bile salts, and pigments. Membrane transporters in hepatocytes transfer the drug into bile.
...
Excreção de drogas: vias pulmonares e glandulares
Drugs are excreted through various unconventional routes, including the lungs, breast milk, and saliva.
In the lungs, volatile drugs diffuse into the ...
Excreção de drogas: rotas diversas
Various bodily processes, including sweating, tears, and the digestive system, contribute to drug excretion.
Nonionized lipophilic drugs passively diffuse ...
Depuração de medicamentos: visão geral
A drug that enters the body gets eliminated by the kidneys and liver through urine or bile, respectively. A pharmacokinetic parameter, drug clearance, ...
Modelos de depuração: Modelos fisiológicos
Drug clearance features irreversible drug removal from any organ in the body.
Physiological models determine clearance through an individual organ, ...
Modelos de folga: Modelos de compartimento
Clearance directly measures drug elimination from the central compartment, which comprises plasma and highly perfused organs like kidneys and liver.
...
Modelos de folga: Modelos não compartimentais
Typically, clearance describes the drug elimination from the body using compartment models.
An alternative, the noncompartmental approach, estimates ...
Depuração renal de medicamentos: visão geral
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 ...
Depuração renal de drogas: comparação entre métodos de excreção renal
Renal clearance is the summation of kidney filtration, secretion, and reabsorption calculated by a specific equation.
It is typically associated with the ...
Fatores que afetam a depuração renal: propriedades físico-químicas do medicamento e níveis plasmáticos
Various factors impact a drug's renal clearance, including its physical-chemical properties and plasma levels.
Molecular size, lipid solubility, and ...
Fatores que afetam a depuração renal: distribuição de medicamentos e interações medicamentosas
Renal clearance, pivotal in drug elimination, can be affected by drug distribution and interactions.
Drugs with a large distribution volume or bound to ...
Fatores que afetam a depuração renal: Insuficiência renal
Renal dysfunction significantly impairs renal drug clearance.
Renal failure can be caused by various factors.
Uremia, characterized by impaired glomerular ...
Insuficiência renal: ajustes de dose
In patients with renal impairment, drugs exhibit altered pharmacokinetics.
Reduced renal clearance and elimination rate result in prolonged elimination ...
Determinação da Depuração Renal do Medicamento: Métodos Gráficos e de Ponto Médio
Renal clearance can be determined using graphical and midpoint methods.
In the graphical method, clearance can be calculated and obtained by plotting the ...
Depuração hepática de medicamentos: depuração restritiva e não restritiva
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 ...
Depuração hepática de drogas: efeito da ligação às proteínas
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 ...
Depuração hepática de medicamentos: papel dos transportadores
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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