Clinical Pharmacokinetics Flashcards
(16 cards)
What is the primary goal of clinical pharmacokinetics?
The primary goal of clinical pharmacokinetics is to apply pharmacokinetic principles to individual patient care, ensuring efficacy while minimizing toxicity.
How does clinical pharmacokinetics differ from traditional pharmacokinetics?
Traditional pharmacokinetics focuses on general drug movement, while clinical pharmacokinetics applies these principles to optimize patient-specific therapy.
What are the key processes involved in pharmacokinetics (ADME), and how do they influence drug behavior?
ADME (Absorption, Distribution, Metabolism, Excretion) determines how drugs behave in the body, affecting their therapeutic effect and elimination.
How is pharmacokinetic data used to determine drug dosing regimens?
Pharmacokinetic data helps determine loading doses, maintenance doses, and dosing intervals based on clearance, half-life, and bioavailability.
What role does therapeutic drug monitoring (TDM) play in pharmacokinetics?
TDM ensures safe drug levels in patients, particularly for drugs with a narrow therapeutic index like digoxin and warfarin.
Why do certain drugs require individualized dosing adjustments?
Certain drugs require individualized dosing due to genetic differences, renal or hepatic dysfunction, and other patient-specific factors.
What is volume of distribution (Vd), and how does it affect drug distribution?
Vd represents the apparent volume in which a drug distributes. High Vd means more tissue distribution, while low Vd means drug remains in plasma.
How does drug clearance (CL) determine the rate at which a drug is eliminated?
Clearance determines how quickly a drug is eliminated, affecting dosing frequency and steady-state drug levels.
Why is half-life (t½) an important factor in dosing schedules?
Half-life dictates how long it takes for 50% of the drug to be eliminated, impacting dosing schedules and steady-state achievement.
How does age affect drug metabolism and clearance?
Neonates have immature enzymes leading to slower metabolism, while elderly patients have reduced renal clearance, requiring dose adjustments.
What pharmacokinetic changes occur in pregnant patients?
Pregnancy increases blood volume and metabolism, altering drug distribution and clearance, requiring dose modifications.
How does body weight influence drug distribution and dosing?
Obese patients may need higher doses for lipophilic drugs, while hydrophilic drugs distribute in plasma water, requiring lean body weight adjustments.
What is nonlinear pharmacokinetics, and how does it affect drug dosing?
Nonlinear pharmacokinetics occurs when elimination processes become saturated, leading to disproportionate increases in drug levels, as seen with phenytoin.
How does pharmacokinetics help in designing extended-release formulations?
Extended-release formulations slow drug absorption and prolong action using controlled-release mechanisms like osmotic pumps and polymer coatings.
What are pharmacokinetic drug interactions, and how do they impact therapy?
Pharmacokinetic drug interactions occur when drugs affect metabolism; enzyme inhibitors (e.g., ketoconazole) increase drug levels, while inducers (e.g., rifampin) decrease them.
Why do some drugs exhibit saturation kinetics, and what are the clinical implications?
Saturation kinetics means drug elimination is constant at high doses, leading to toxicity with small dose increases, as seen with phenytoin.
