Term
| What is the equation for loading dose? |
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Definition
|
|
Term
| What is the equation for maintenance dose? |
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Definition
|
|
Term
| What is the primary determinant for calculating loading dose? |
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Definition
|
|
Term
| What is the primary determinant for calculating loading dose? |
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Definition
|
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Term
| What is the equation for calculating Clearance at steady state? |
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Definition
|
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Term
| What is the rate of drug administration equal to at steady state? |
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Definition
| the rate of drug elimination |
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Term
| How many half lives does it take to attain steady state concentration? is this dosage dependent or independent? |
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Definition
4 half lives
dosage independent |
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Term
| What is the equation for infusion rate? |
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Definition
|
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Term
| Which order of kinetics do most drugs obey clinically? |
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Definition
|
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Term
| Which order of kinetics has a constant half life? |
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Definition
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Term
| Which order of kinetics has a fixed amount of drug that is metabolized per unit time? |
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Definition
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Term
| Which order of kinetics has the equation C = C0 - kt |
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Definition
|
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Term
| Which order of kinetics has distribution and elimination phases? |
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Definition
|
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Term
| what is dose-dependent kinetics? |
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Definition
| when a drug's elimination is mediated predominantly by metabolism |
|
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Term
| what is the equation for dose-dependent kinetics? |
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Definition
| dC/dt = -(Vmax x C)/(Km +C) |
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Term
| when concentrations of a drugs are well below the Km of the metabolic enzymes, will the drug follow first-order or zero-order kinetics of elimination? |
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Definition
|
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Term
| When concentrations of a drug are well above the Km of metabolic enzymes, will the drug follow first-order or zero-order kinetics of elimination? |
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Definition
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Term
| what order of elimination do phenytoin, apirin and ethanol follow? |
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Definition
| at low doses and plasma concentrations, they follow apparent first-order kinetics, but at higher doses and plasma concentrations the metabolic pathways become saturated and they exhibit zero-order kinetics |
|
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Term
| what are the "primary" pharmacokinetic parameters? |
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Definition
| elimination clearance and volume of distribution |
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Term
| How do you calculate the time to reach 90% steady state concentration? |
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Definition
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Term
| How do you determine the fraction of dose needed for a pt in renal failure? |
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Definition
multiply normal dose by clearance ratio
CL(RF)/CL(normal) |
|
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Term
| what three ways can dosing rate be reduced? |
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Definition
1. reducing the dose
2. increasing the dosing interval
3. both |
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Term
| if a pt's steady state was above the tolerated concentration by the pt would you reduce the dose or increase the interval? |
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Definition
|
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Term
| what is the most commonly used measure for approximating GFR? |
|
Definition
| creatinine clearance rate (CrCL) |
|
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Term
| Is CrCL the same as clearance of the drug? |
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Definition
NO
it only provides a relative measure of how well the kidney is functioning |
|
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Term
| What is the Cockcroft and Gault equation used for? |
|
Definition
| to estimate creatinine clearance |
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Term
| What variables do you need for the Cockcroft and Gault eq? |
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Definition
| age, body weight, serum [Cr] |
|
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Term
| How does CrCL depend on sex? |
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Definition
| reduce by 15% for females (multiply by .85) |
|
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Term
| what is the normal range for serum creatinine concentration? |
|
Definition
|
|
Term
| what is the normal range for creatinine clearance? |
|
Definition
males: 110-120 mL/min
females: 100-110 mL/min |
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Term
| what three things does hepatic drug clearance depend on? |
|
Definition
-protein binding
-liver blood flow
-intrinsic clearance |
|
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Term
| What equation is used for hepatic drug clearance? |
|
Definition
Rowland's Equation
CL(H) = Qx [(fxCLi)/(Q+(fxCLi)]
Q = liver blood flow
f = free fraction (unbound)
CLi = intrinsic clearance |
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Term
| If flow is much greater than (f x CL(int)), what does that mean about the drug? |
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Definition
| the drug has little first pass metabolism |
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Term
| How is the Rowland's equation rearranged when Q>> (f x CL(int))? |
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Definition
|
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Term
| if Q>>(f x CL(int)), is there high or low hepatic extraction? |
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Definition
|
|
Term
| Will a drug have more or less "first pass metabolism" when given orally? |
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Definition
|
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Term
| Which will have a greater effect on hepatic clearance: a change in binding or a change in liver blood flow? |
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Definition
|
|
Term
| what 2 drugs are given as classic examples of drugs with low hepatic extraction? |
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Definition
|
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Term
| what Cytochrome P450 gene is responsible for the metabolism of S-warfarin? |
|
Definition
|
|
Term
| What happens in patients with variant CYP2C9 alleles? |
|
Definition
| they have a low warfarin dose requirement |
|
|
Term
How does Rowland's equation change for drugs with high hepatic extraction?
Q << f x CLi |
|
Definition
|
|
Term
| What terms are used to describe high hepatic extraction? |
|
Definition
non-restrictive hepatic clearance
flow-dependent clearance |
|
|
Term
| what conditions will reduce hepatic clearance? |
|
Definition
-conditions that reduce blood flow such as CHF and hypotension
-hepatic blood flow also decreases with age
-beta blockers can reduce hepatic blood flow |
|
|
Term
| what are the two classic examples given for drugs with high hepatic extraction? |
|
Definition
| lidocaine and propranolol |
|
|
Term
| what are the two major divisions of pharmacology? |
|
Definition
| pharmacodynamics and pharmacokinetics |
|
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Term
| is the quantitative description of ADME part of pharmacodynamics or pharmacokinetics? |
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Definition
|
|
Term
| is the time-course action of the drug a part of pharmacodynamics or pharmacokinetics? |
|
Definition
|
|
Term
| what division of pharmacology deals with the mechanisms of action of the drugs? |
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Definition
|
|
Term
| are drug-receptor interactions part of pharmacodynamics or pharmacokinetics? |
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Definition
|
|
Term
| how does liver metabolism affect the bioavailability of lidocaine or propranolol? |
|
Definition
| only about 30-35% of a dose will reach systemic circulation unchanged |
|
|
Term
| Does gentamicin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does phenytoin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does penicillin G undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does digoxin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does tobramycin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does procainamide undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does warfarin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does theophylline undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does vancomycin undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| Does lidocaine undergo renal clearance, hepatic clearance, or both? |
|
Definition
|
|
Term
| what does the time to reach steady state depend on? |
|
Definition
|
|
Term
| what dose the steady state concentration depend on? |
|
Definition
| dosing rate and elimination clearance |
|
|
Term
| what is aspirin used for? |
|
Definition
analgesic
antipyretic
anti-inflammatory |
|
|
Term
| what are some pharmacokinetic characteristics of aspirin? |
|
Definition
| approximates zero order kinetics of elimination at high concentration |
|
|
Term
| what is digoxin used for? |
|
Definition
atrial fibrillation
atrial flutter
congestive heart failure |
|
|
Term
| what are some pharmacokinetic characteristics of digoxin? |
|
Definition
-narrow therapeutic index
-large Vd
-high bioavailability
-two-compartment distribution profile |
|
|
Term
| what is ethyl alcohol used for? |
|
Definition
|
|
Term
| what are some pharmacokinetic characteristics of ethyl alcohol? |
|
Definition
-concentration-dependent kinetics of elimination
-zero order at high concentrations |
|
|
Term
| what are gentamicin and tobramycin? |
|
Definition
| aminoglycoside antibiotics used to treat many types of bacterial infections, particularly Gram-negative bacterial infections |
|
|
Term
| what are some pharmacokinetic characteristics of gentamicin and tobramycin? |
|
Definition
Cleared exclusively by the kidney, both can be highly nephrotoxic, particularly if multiple doses accumulate over a course of
treatment—usually dosed by body weight and serum levels are monitored during treatment.
Tobramycin does not pass the gastro-intestinal tract, so for systemic use it can only be given intravenously or intramuscularly. |
|
|
Term
| what is lidocaine used for? |
|
Definition
| local anesthetic and antiarrythmic |
|
|
Term
| what are some pharmacokinetic characteristics of lidocaine? |
|
Definition
| Low bioavailability (extensive first-pass metabolism in the liver). Lidocaine hydrochloride is available in various forms including: injectable (for i.v. injection/infusion or as local anesthetic), dermal patch, nasal instillation/spray, oral (gel, liquid), topical (gel, liquid, or patch). Given i.v. it distributes rapidly to tissues. Eliminated primarily by metabolism in the liver. Two-compartment distribution profile. |
|
|
Term
| What is penicillin G used for? |
|
Definition
| antibiotic used in the prophylaxis and treatment of infections caused by Gram-positive bacteria |
|
|
Term
| what are some pharmacokinetic characteristics of penicillin G? |
|
Definition
| Elimination rate is dependent on renal function and is greatly reduced in renal failure: t½ can increase as much as 20-fold. |
|
|
Term
| what is phenytoin used for? |
|
Definition
| antiepileptic - acts by stabilizing the inactive state of voltage gated sodium channels |
|
|
Term
| what are some pharmacokinetic characteristics of phenytoin? |
|
Definition
Approximates zero-order kinetics of
elimination at therapeutic concentrations. High bioavailability. Eliminated primarily by metabolism in the liver. Highly protein-bound. |
|
|
Term
| what is propranolol used for? |
|
Definition
| B-blocker, mainly used in the treatment of hypertension |
|
|
Term
| what are some pharmacokinetic characteristics of propranolol? |
|
Definition
| extensive first-pass metabolism (low bioavailability), lipid soluble, large Vd |
|
|
Term
| what is theophylline used for? |
|
Definition
| a methylxanthine drug used in therapy for respiratory diseases such as COPD or asthma |
|
|
Term
| what are some pharmacokinetic characteristics of theophylline? |
|
Definition
| Theophylline has a narrow therapeutic index. It approaches zero-order kinetics of elimination at high concentrations. High bioavailability. Eliminated primarily by metabolism in the liver |
|
|
Term
| what is vancomycin used for? |
|
Definition
A glycopeptide antibiotic
used in the prophylaxis and treatment of infections caused by Gram-positive bacteria |
|
|
Term
| what are some pharmacokinetic characteristics of vancomycin? |
|
Definition
Vancomycin must be given intravenously,
because it is not absorbed orally (it is a large hydrophilic molecule which partitions poorly across the gastrointestinal mucosa). It is eliminated by the kidney |
|
|
Term
| what is warfarin used for? |
|
Definition
|
|
Term
| what are some pharmacokinetic characteristics of warfarin? |
|
Definition
| Warfarin has a long half life. It may be given orally once per day, but it is highly proteinbound and often takes several days to reach therapeutic effect. High bioavailability. Eliminated primarily by metabolism in the liver |
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