Pharmacokinetics Questions and Answers | Latest Version | 2025/2026 | Correct & Verified

Pharmacokinetics Questions and Answers | Latest Version | 2025/2026 | Correct & Verified What is the significance of drug half-life in designing tapering schedules? It determines how gradually a drug should be reduced to avoid withdrawal or toxicity How does hypoalbuminemia affect highly protein-bound drugs? It increases the free, active drug concentration, raising the risk of adverse effects What is the effect of impaired hepatic blood flow on drug metabolism? It can reduce first-pass metabolism, increasing systemic drug levels How does pH trapping affect drug excretion? Altering urine pH can increase the elimination of weak acids or bases by ionizing the drug What is the importance of the peak plasma concentration (Cmax)? It indicates the highest drug level in the blood, helping assess efficacy and toxicity 2 How does the time to peak concentration (Tmax) affect drug action? It determines the onset of therapeutic effect What is the effect of chronic kidney disease on drug half-life? It generally prolongs half-life due to decreased clearance Why is drug clearance important in dose adjustments? It helps calculate the proper dose to maintain therapeutic levels without toxicity What is the effect of age-related changes in gastric emptying on drug absorption? Slower gastric emptying may delay onset of action for oral drugs How does enterohepatic recirculation prolong drug action? Drugs excreted in bile are reabsorbed, maintaining plasma concentration longer What is the difference between total drug concentration and free drug concentration? Total includes both bound and unbound drug; free concentration is pharmacologically active 3 How can fluid shifts affect drug distribution in critically ill patients? Edema or dehydration can dilute or concentrate drug levels, altering effectiveness What is the role of transport proteins in drug pharmacokinetics? They facilitate drug uptake and efflux across membranes, affecting absorption and excretion How does obesity affect the pharmacokinetics of hydrophilic drugs? Hydrophilic drugs have lower volume of distribution and may require lower doses What is the effect of liver enzyme induction on oral contraceptives? Increased metabolism may reduce efficacy, leading to contraceptive failure How does malnutrition influence drug pharmacokinetics? It can reduce plasma protein levels and impair drug metabolism, altering drug effect What is the significance of renal tubular secretion in drug excretion? It actively removes drugs from blood into urine, important for drugs cleared this way 4 How can drug accumulation occur in repeated dosing? If the dosing interval is shorter than the drug’s half-life, leading to higher plasma levels How does acute inflammation affect drug metabolism? Inflammation can downregulate liver enzymes, slowing metabolism What is the effect of heart failure on drug distribution? Reduced cardiac output may decrease perfusion to tissues, altering drug levels How does smoking cessation influence drug metabolism? It can reduce enzyme induction, leading to higher drug levels of previously induced drugs What is the significance of apparent volume of distribution (Vd) in drug dosing? It helps estimate the loading dose required to achieve therapeutic plasma concentration How do genetic polymorphisms in CYP450 enzymes affect drug response? They can make individuals rapid or poor metabolizers, affecting efficacy and toxicity 5 How does protein-energy malnutrition affect drug binding? Decreased albumin reduces binding of acidic drugs, increasing free active drug What is the importance of therapeutic drug monitoring (TDM)? To maintain drug concentration within the therapeutic window and avoid toxicity How does fever affect pharmacokinetics?