2313517
Description
Flashcards by Vicky Reese, updated more than 1 year ago
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Created by Vicky Reese
over 9 years ago
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| Question | Answer |
| Rational Use of Drugs | Assumes that a particular concentration of a drug will have the desired therapeutic effect and that adverse effects will be negligible |
| Therapeutic Range | The range of drug concentrations having a high probability of producing the desired therapeutic effect and a low probability of producing adverse effects |
| Steady-State Plasma Drug Concentration | Maintains the desired pharmacological response |
| Dosing Regimen | • The size of the dose • The dosing frequency |
| Pharmacokinetics | • Plays a major role in: - Establishing the initial dosing regimen - Adjusting the regimen to deal with a lack of response or to reduce symptoms of toxicity |
| Plasma Concentration-Time Profile of A Drug | • This measure graphically demonstrates the relationship between the plasma drug concentration and therapeutic response or toxicity over time |
| BIOAVAILABILITY | • The proportion of the administered dose that reaches the systemic circulation intact • Usually expressed as a % F = fg x fH |
| AUC (area under the plasma concentration versus time curve) | Total area under the curve that describes the concentration of the drug in the systemic circulation as a function of time post dose (normally 0 - infinity) |
| Clearance (CL) | • The ability of either an individual organ or the body to eliminate a drug |
| Steady state | The rate of drug administration equals the rate of drug elimination & the plasma drug concentration remains constant At steady state: Elimination rate = maintenance dose rate (DR) |
| Volume of Distribution (V) | The volume in which the amount of drug in the body would need to be uniformly distributed to produce the observed concentration in the blood V = total amount of drug in body (A)/drug concentration (C) |
| Clinical use of Volume of Distribution | 1.) Provides an indication of accumulation of drugs in extravascular (tissue) compartments (e.g. fat, muscle) 2.) A major determinant of half-life of a drug 3.) On occasion, it is necessary to achieve a high plasma concentration quickly to produce the desired therapeutic response |
| Loading Dose | • Administered to 'fill up' the volume of distribution • May be given to produce rapid pharmacological effect Loading dose = volume of distribution (V) x target plasma concentration (C) |
| Half-life (t1/2) | • Time taken for the blood or plasma drug concentration to fall by one-half (50%) t1/2 = 0.693 x V/ CL |
| Half-life is a major determinant of the ff. | • duration of action of a drug after a single dose • time taken to reach steady state with chronic dosing • dosing frequency required to avoid massive fluctuations in plasma drug concentration during the dosing interval |
| First order kinetics | Assumes a constant proportion of the drug is eliminated per unit time (as dose and blood concentration of drug increases, the rate of elimination increase) |
| SATURABLE METABOLISM | the situation in which the enzyme metabolizing drug reaches maximum capacity and rate of metabolism CAN'T increase further as dose increases |
| Zero-order Kinetics | • rate of elimination does NOT increase in proportion to dose and concentration • metabolism is saturate & CL & t1/2 are not constant (CL continually decreases & t1/2 continually increase as the dose & blood concentration increase) |
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