Pharmacokinetics

A 70-kg adult needs an immediate plasma concentration (Cp) of 10 mg/L; Vd = 0.6 L/kg; IV bolus. What loading dose is required?

A drug has CL = 3 L/h. For a target steady-state concentration (Css) of 10 mg/L by continuous IV infusion, what rate is needed?

For a drug with Vd = 50 L and CL = 5 L/h, what is the half-life?

About how long to reach >95% of steady state for a first-order drug started as a continuous infusion?

After 200 mg oral dose, AUC_oral = 60 mg·h/L; after 100 mg IV, AUC_IV = 80 mg·h/L. What is oral bioavailability (F)?

Which statement describes first-order elimination?

Which drug commonly exhibits zero-order elimination at usual or high concentrations?

Which change increases the volume of distribution of a highly protein-bound acidic drug?

Renal elimination of a weak acid (e.g., salicylate) is enhanced by:

If a drug is cleared solely by glomerular filtration with no secretion/reabsorption, renal clearance equals:

For a high-extraction hepatic drug (E ≈ 0.8), systemic clearance is most dependent on:

For a low-extraction hepatic drug (E ≈ 0.1), clearance is most affected by:

An IV bolus of 500 mg gives extrapolated C0 = 8 mg/L. What is Vd?

If CL stays constant, doubling a continuous infusion rate will:

Oral regimen: F = 0.6, Dose = 300 mg q8h, CL = 3 L/h. What is Cavg at steady state?

Approximately what fraction of steady state is reached after 3.3 half-lives with continuous infusion?

A strong CYP3A inducer (e.g., rifampin) co-administered with an oral CYP3A substrate will:

Grapefruit juice (intestinal CYP3A/P-gp inhibitor) typically:

Phenytoin displays Michaelis–Menten elimination; clinical implication is:

Total phenytoin 8 mcg/mL, albumin 2.0 g/dL; corrected level (Sheiner–Tozer)?

For a flow-limited (high-extraction) drug, an increase in cardiac output most likely:

After an IV bolus, the initial steep decline in a two-compartment model primarily reflects:

Vancomycin TDM: when to draw a trough in a q12h regimen?

IV dose 100 mg yields AUC = 25 mg·h/L. What is total clearance?

Oral dose 200 mg with F = 0.5 gives AUC = 20 mg·h/L. What is CL?

In renal failure for a primarily renally cleared drug, which parameter typically increases?

Which drug property favors removal by hemodialysis?

If t½ = 8 h, what is the elimination rate constant k?

Clearance decreases by 50% with unchanged Vd. To maintain same Css with same dosing interval, you should:

Controlled-release product shows “flip-flop” kinetics when:

Which covariate most strongly influences Vd for hydrophilic drugs?

Peak-to-trough fluctuation in multiple dosing is minimized when:

To enhance renal excretion of a weak base (e.g., amphetamine), urine should be:

What fraction of steady state is reached after 2 half-lives with continuous infusion?

Oral loading dose needed for target Cp = 5 mg/L, Vd = 30 L, F = 0.5?

In cirrhosis for a high-extraction oral drug, the most appropriate change is:

Enzyme induction typically:

For a multiple-dose regimen at steady state, Cavg depends primarily on:

As plasma protein binding becomes saturated at higher concentrations:

Hepatic extraction ratio E = (Ca − Cv)/Ca. If Ca = 10 mg/L, Cv = 7 mg/L, and hepatic blood flow Q = 90 L/h, hepatic clearance is:

A drug has t½ = 8 h and is dosed q12h. What is the accumulation factor (R) at steady state?

For a drug with t½ = 6 h started as a continuous infusion, about how long to reach ~90% of steady state?

Target digoxin Cp = 1.0 ng/mL; Vd ≈ 7 L/kg; weight 70 kg; oral F ≈ 0.7. What oral loading dose?

Extended-interval gentamicin 7 mg/kg IV bolus in a patient with Vd 0.25 L/kg. What is the initial concentration (C₀)?

Vancomycin AUC₍₂₄₎ target 400–600 mg·h/L. If CL = 4 L/h, what total daily dose achieves AUC ≈ 500?

For a first-order drug at steady state, time to reach steady state depends primarily on:

A renally cleared drug is dosed 100 mg q12h at CrCl 100 mL/min. If CrCl falls to 50 mL/min (same τ), what dose maintains similar exposure?

If Vd = 40 L and CL decreases to 2 L/h, what is the half-life?

For an IV bolus multiple-dose regimen: Cmax,ss = 20 mg/L, k = 0.20 h⁻¹, τ = 8 h. What is Cmin,ss?

A CYP3A inhibitor doubles oral bioavailability of a substrate from F=0.3 to F=0.6 with unchanged dose and CL. What happens to average steady-state concentration?

After an IV bolus, C at 2 h = 12 mg/L and at 8 h = 3 mg/L. What is the half-life?

Target phenytoin concentration 15 mg/L; Vd ≈ 0.7 L/kg; weight 80 kg. Approximate IV loading dose (ignore saturation for estimate)?

A theophylline infusion is planned with CL = 4.5 L/h and desired Css = 12 mg/L. What infusion rate?

Vancomycin 1,000 mg infused over 1 h; Vd = 40 L; k = 0.10 h⁻¹. Approximate concentration at end of infusion (single dose)?

Which adjustment will raise trough concentrations more effectively (relative to peak) in a linear one-compartment regimen?

If hepatic blood flow Qh = 90 L/h and hepatic clearance CLh = 18 L/h, what is the hepatic extraction ratio (E)?

For a low-extraction, highly protein-bound drug, the free fraction (fu) doubles due to hypoalbuminemia. At the same dose, what happens at steady state?

Which change reduces peak–trough fluctuation without changing total daily dose for a linear drug?

Oral drug with F = 0.5, CL = 3.5 L/h, target Cavg = 10 mg/L, τ = 12 h. What maintenance dose per dose?

Gentamicin target: peak ~8 mg/L, trough <1 mg/L q24h; k = 0.25 h⁻¹; Vd = 0.25 L/kg; weight 80 kg. What dose and interval meet targets?