Linear Pharmacokinetics Quiz

<p>Both phenytoin and salicylic acid</p> Signup and view all the answers

<p>Linear pharmacokinetics</p> Signup and view all the answers

<p>Warfarin is highly bound to serum albumin, resulting in a small free fraction in the blood</p> Signup and view all the answers

<p>Serum concentrations decline in a curvilinear fashion</p> Signup and view all the answers

<p>The serum concentrations decrease in a linear fashion after absorption and distribution phases are complete</p> Signup and view all the answers

<p>$t_{1/2} = 0.693 / k_e$</p> Signup and view all the answers

<p>The half-life determines the time to reach steady state during continuous dosing and the dosage interval</p> Signup and view all the answers

<p>95%</p> Signup and view all the answers

<p>$t_{1/2} = (0.693 \cdot V)/Cl$ and $k_e = Cl/V$</p> Signup and view all the answers

<p>8 hours</p> Signup and view all the answers

<p>They can change due to a change in either clearance (Cl) or volume of distribution (V).</p> Signup and view all the answers

<p>99%</p> Signup and view all the answers

<p>The rate of drug elimination is directly proportional to the drug concentration in the body.</p> Signup and view all the answers

<p>The rate of drug administration is equal to the rate of drug elimination.</p> Signup and view all the answers

<p>The volume of distribution is constant and independent of the drug concentration.</p> Signup and view all the answers

<p>The steady-state concentration doubles.</p> Signup and view all the answers

<p>It allows for easier prediction of steady-state concentrations and dosage adjustments.</p> Signup and view all the answers

<p>The clearance of the drug decreases as the dose or concentration increases.</p> Signup and view all the answers

<p>The clearance rate decreases.</p> Signup and view all the answers

<p>The volume of distribution (V).</p> Signup and view all the answers

<p>The therapeutic range will increase disproportionately.</p> Signup and view all the answers

<p>Cl = Vmax / (Km + C)</p> Signup and view all the answers

<p>Half-life is inversely proportional to clearance and directly proportional to volume of distribution.</p> Signup and view all the answers

<p>$160 mg\cdot h/L$</p> Signup and view all the answers

<p>Steady-state concentration is directly proportional to dosage rate.</p> Signup and view all the answers

<p>$10 \mu g/mL$</p> Signup and view all the answers

<p>24 hours</p> Signup and view all the answers

<p>Clearance</p> Signup and view all the answers

<p>Carbamazepine</p> Signup and view all the answers

<p>Its clearance depends on the drug concentration in a nonlinear manner</p> Signup and view all the answers

<p>Increase less than expected</p> Signup and view all the answers

<p>Clearance</p> Signup and view all the answers

<p>Michaelis-Menten kinetics</p> Signup and view all the answers

<p>Maintenance dose is halved</p> Signup and view all the answers

<p>$10-20$ μg/mL</p> Signup and view all the answers

<p>$\text{Steady-state concentrations} &lt; \text{Expected increase}$</p> Signup and view all the answers

<p>It remains constant regardless of dose</p> Signup and view all the answers

<p>Serum concentrations decline in a curvilinear fashion initially, but decrease linearly after absorption and distribution phases are complete.</p> Signup and view all the answers

<p>The elimination rate constant is the terminal slope of the serum concentration/time curve after absorption and distribution phases are complete. It indicates how quickly drug serum concentrations decline in a patient.</p> Signup and view all the answers

<p>Half-life determines the time to reach steady state during continuous dosing of a drug. It also influences the dosage interval for the drug.</p> Signup and view all the answers

<p>The relationship between half-life and ke is defined by the equation: t1/2 = 0.693/ke. Once one parameter is known, the other can be easily computed.</p> Signup and view all the answers

<p>The elimination phase is when serum concentrations decrease linearly after absorption and distribution phases are complete. It is crucial for determining the duration of drug action and dosing intervals.</p> Signup and view all the answers

<p>Linear pharmacokinetics refers to a situation where steady-state drug concentrations change proportionally with dose. An example of a drug that follows linear pharmacokinetics is aspirin.</p> Signup and view all the answers

<p>A straight line plot indicates that the drug follows linear pharmacokinetics, where steady-state serum concentrations change proportionally with dose.</p> Signup and view all the answers

<p>In linear pharmacokinetics, when the dosage rate is doubled, the steady-state serum concentration will also double.</p> Signup and view all the answers

<p>Saturable pharmacokinetics occur when the processes removing the drug from the body become saturated. When this happens, steady-state concentrations may increase more than expected after a dosage increase.</p> Signup and view all the answers

<p>Two typical explanations for this phenomenon are changes in clearance mechanisms or drug interactions affecting metabolism.</p> Signup and view all the answers

<p>Steady state is important as it allows for assessment of patient response and computation of new dosage regimens based on serum or blood concentrations.</p> Signup and view all the answers

<p>Pharmacokinetics refers to what the body does to the drug, while pharmacodynamics refers to what the drug does to the body.</p> Signup and view all the answers

<p>Linear pharmacokinetics involve a constant drug administration rate that equals the rate of metabolism and excretion, leading to steady state. Non-linear pharmacokinetics do not follow this constant relationship.</p> Signup and view all the answers

<p>Volume of distribution refers to the theoretical volume that would be necessary to contain the total amount of drug in the body at the same concentration observed in the blood.</p> Signup and view all the answers

<p>A loading dose is calculated by multiplying the target concentration by the volume of distribution.</p> Signup and view all the answers

<p>Half-life becomes longer</p> Signup and view all the answers

<p>Fraction (F)</p> Signup and view all the answers

<p>F = AUCPO/AUCIV</p> Signup and view all the answers

<p>Inverse relationship</p> Signup and view all the answers

<p>Clearance decreases</p> Signup and view all the answers

<p>The clearance of a drug is not a constant but is concentration- or dose-dependent. As the dose or concentration increases, the clearance rate decreases as the enzyme approaches saturable conditions.</p> Signup and view all the answers

<p>As the steady-state concentration of phenytoin increases from 10 mg/L to 20 mg/L, clearance decreases from 36 L/d to 21 L/d.</p> Signup and view all the answers

<p>Steady-state concentrations are directly proportional to the dosing rate.</p> Signup and view all the answers

<p>The volume of distribution (V) is unaffected by saturable metabolism and is still determined by physiological parameters and the unbound concentration of the drug.</p> Signup and view all the answers

<p>For drugs exhibiting linear pharmacokinetics, the half-life and elimination rate constant remain constant and independent of the drug dose or concentration.</p> Signup and view all the answers

<p>$t_{1/2} = (0.693 ⋅ V)/Cl , ke = Cl/V$</p> Signup and view all the answers

<p>Dose intervals are determined by the half-life of the drug. For example, if a drug has a half-life of 8 hours, it should be given every 8 hours to maintain steady-state concentrations.</p> Signup and view all the answers

<p>Both the half-life and elimination rate constant are affected by changes in clearance. An increase in clearance leads to a decrease in the half-life and increase in the elimination rate constant.</p> Signup and view all the answers

<p>Maintaining the dosage interval ensures that the drug is administered frequently enough to prevent serum concentrations from falling below or rising above the therapeutic range.</p> Signup and view all the answers

<p>The half-life and elimination rate constant are considered dependent parameters because their values are influenced by the drug's clearance and volume of distribution.</p> Signup and view all the answers

<p>Predictability and easier dosing calculations</p> Signup and view all the answers

<p>Exponentially</p> Signup and view all the answers

<p>A straight line is obtained</p> Signup and view all the answers

<p>No direct relationship</p> Signup and view all the answers

<p>Drug clearance remains constant regardless of drug concentration</p> Signup and view all the answers

<p>Steady-state concentration doubles</p> Signup and view all the answers

<p>Volume of distribution remains constant</p> Signup and view all the answers

<p>Steady-state concentrations are proportional to dose rate</p> Signup and view all the answers

<p>160 mg⋅h/L</p> Signup and view all the answers

<p>Determining dosing intervals</p> Signup and view all the answers