Eliminating drugs from the body is a vital process that occurs through excretion or metabolism. Understanding the kinetics of drug elimination is crucial for drug development, dosage determination, and optimizing patient outcomes.
Drug clearance depends on the rate of drug elimination and its plasma concentration. Another important parameter is a drug's half-life, which is the time required for its concentration to decrease by half. In most cases, drug clearance follows first-order kinetics, where a constant fraction of the drug is eliminated per unit of time. This means that as the drug concentration increases, its elimination rate also increases. The relationship between drug concentration and time is exponential.
However, certain drugs, like phenytoin, aspirin, omeprazole, and fluoxetine, exhibit zero-order kinetics. When administered at high therapeutic doses, these drugs saturate the enzymes responsible for their metabolism. As a result, only a fixed amount of the drug is eliminated at a constant rate, regardless of its concentration. The plot of drug concentration versus time in zero-order kinetics is linear, indicating that increasing the drug concentration does not affect its elimination rate.
Do Capítulo 6:
Now Playing
Pharmacokinetics: Drug Excretion and Clearance
74 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
45 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
35 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
45 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
27 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
29 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
37 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
26 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
27 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
13 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
12 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
20 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
30 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
27 Visualizações
Pharmacokinetics: Drug Excretion and Clearance
15 Visualizações
See More
Copyright © 2025 MyJoVE Corporation. Todos os direitos reservados