TDM Flashcards
The term PHARMACOKINETICS refers to the:
-Relationship between drug dose and the drug blood level
-Concentration of drug at its sites of action
-Relationship between blood concentration and therapeutic response
-The relationship between blood and tissue drug levels
Relationship between drug dose and the drug blood level
Pharmacokinetics is the mathematical expression of the relationship between drug dose and drug blood level. When the appropriate formula is applied to quantitative measures of drug dose, absorption, distribution, and elimination, the blood concentration can be accurately determined.
The term PHARMACODYNAMICS is an expression of the relationship between:
-Dose and physiological effect
-Drug concentration at target sites and physiological effect
-Time and serum drug concentration
-Blood and tissue drug levels
Drug concentration at target sites and physiological effect
Pharmacodynamics is the relationship between the drug concentration at the receptor site (tissue concentration) and the response of the tissue to that drug. For example, the relationship between lidocaine concentration in the heart muscle and the duration of the action potential of Purkinje fibers.
The study of PHARMACOGENOMICS involves which type of testing?
-Family studies to determine the inheritance of drug resistance
-Testing drugs with cell cultures to determine the minimum toxic dosage
-Testing for single nucleotide polymorphisms known to affect drug metabolism
-Comparison of dose-response curves between family members
Testing for single nucleotide polymorphisms known to affect drug metabolism
Pharmacogenomics refers to the study of genes that affect the performance of a drug in an individual. One method is to test for single nucleotide polymorphisms (SNPs) using DNA microarrays in genes such as those that code for the cytochrome P450 enzymes involved in the metabolism of many drugs. Genetic variations of one such enzyme may account for individual pharmacokinetic differences and can be used to predict the efficacy of the drug.
Select the five pharmacological parameters that determine serum drug concentration.
-Absorption, anabolism, perfusion, bioactivation, excretion
-Liberation, equilibration, biotransformation, reabsorption, elimination
-Liberation, absorption, distribution, metabolism, excretion
-Ingestion, conjugation, integration, metabolism, elimination
Liberation, absorption, distribution, metabolism, excretion
Liberation is the release of the drug and absorption is the transport of drug from the site of administration to the blood.
Distribution refers to the delivery of the drug to the tissues. It involves dilution and equilibration of the drug in various fluid compartments including the blood, and is influenced by binding to proteins and blood cells.
Metabolism is the process of chemical modification of the drug by cells. This results in production of metabolites with altered activity and solubility.
Excretion is the process by which the drug and its metabolites are removed from the body.
Most common route of drug delivery:
Intravenous
Oral
Rectal
Transcutaneous
Oral
Oral administration is the most common route of delivery.
Drug administration which offers the most direct route with effective delivery to their sites of action:
Intramuscular
Intravenous
Oral
Rectal
Subcutaneous
Intravenous
Intravenous (IV) administration into the circulatory system offers the most direct route with effective delivery to their sites of action.
Drug delivery commonly used in INFANTS and in situations in which oral delivery is unavailable:
Intramuscular
Intravenous
Rectal
Subcutaneous
Rectal
Rectal delivery (suppository) is commonly used in infants and in situations in which oral delivery is unavailable.
Which route of administration is associated with 100% bioavailability?
Sublingual
Intramuscular
Oral
Intravenous
Intravenous
When a drug is administered intravenously, all the drug enters the bloodstream, and therefore, the bioavailable fraction is 1.0.
In pharmacokinetics, serum concentrations ______ when the rate of absorption exceeds distribution and elimination.
Decline
Spuriously decline
Rise
Spuriously rise
Rise
Serum concentrations rise when the rate of absorption exceeds distribution and elimination.
The concentration declines as the rate of elimination and distribution exceeds absorption.
The rate of elimination can only be determined after absorption and distribution are complete.
In pharmacokinetics, the concentration of the drug _____ as the rate of elimination and distribution exceeds absorption.
Declines
Spuriously declines
Rises
Spuriously rises
Declines
Serum concentrations rise when the rate of absorption exceeds distribution and elimination.
The concentration declines as the rate of elimination and distribution exceeds absorption.
The rate of elimination can only be determined after absorption and distribution are complete.
Single most important factor in therapeutic drug monitoring (TDM):
Amount of WBCs in the specimen
Presence of glucose in the specimen
Timing of specimen collection
Volume of specimen
Timing of specimen collection
Timing of specimen collection is the single most important factor in TDM.
In general, trough concentrations for most drugs are drawn right before the next dose; peak concentrations are drawn 1 hour after an orally administered dose.
Specimen of choice for the determination of circulating concentrations of most drugs:
Expectorated sputum
Gastric fluid
Serum or plasma
Urine
Serum or plasma
Serum or plasma is the specimen of choice for the determination of circulating concentrations of most drugs.
Heparinized plasma is suitable for most drug analysis. The calcium-binding anticoagulants add a variety of anions and cations that may interfere with analysis or cause a drug to distribute differently between cells and plasma. As a result, ethylenediaminetetracetic acid (EDTA), citrated and oxalated plasma are not usually acceptable specimens.
Blood sample collection time for peak drug levels:
Varies with the drug, depending on its rate of absorption
Is independent of drug formulation
Is independent of the route of administration
Is 30 minutes after a bolus intravenous injection is completed
Varies with the drug, depending on its rate of absorption
The peak concentration of a drug is the highest concentration obtained in the dosing interval.
For oral drugs, the time of peak concentration is dependent upon their rates of absorption and elimination and is determined by serial blood measurements.
Peak levels for oral drugs are usually drawn 1–2 hours after administration of the dose.
For drugs given intravenously, peak levels are measured immediately after the infusion is completed.
When should blood samples for trough drug levels be collected?
30 minutes after peak levels
45 minutes before the next dose
1–2 hours after the last dose
Immediately before the next dose is given
Immediately before the next dose is given
Trough levels are usually collected just before the next dose is given.
A urine sample is received in the laboratory with the appropriate custody control form, and a request for drug of abuse screening. Which test result would be cause for rejecting the sample?
Temperature after collection 95°F
pH 5.0
Specific gravity 1.005
Creatinine 5 mg/dL
Creatinine 5 mg/dL
Approximately 5 per 1,000 urine samples received for DAU testing have been adulterated by either dilution, substitution, or addition of substances such as glutaraldehyde that interfere with testing.
The majority of these situations can be detected by determining temperature (90°F–100°F) pH (4.5–8.0), specific gravity (1.003–1.019), and creatinine (≥20 mg/dL).
All of the values listed are within the limits of an acceptable sample with the exception of creatinine.
All of the following are cardioactive drugs, except:
Aminoglycoside
Digixon
Procainamide
Quinidine
Aminoglycoside
Aminoglycosides are a group of chemically related antibiotics used for the treatment of infections with gram-negative bacteria that are resistant to less toxic antibiotics.
A BARBITURATE that effectively controls several types of seizures:
Carbamazepine
Phenobarbital
Phenytoin
Valproic acid
Phenobarbital
An orally administered drug used to treat manic depression (bipolar disorder):
Digoxin
Lithium
Phenytoin
Theophylline
Lithium
All of the following are immunosuppressive drugs, except:
Cyclosporine
Phenytoin
Sirolimus (rapamycin)
Tacrolimus
Phenytoin
An anti-neoplastic drug that inhibits DNA synthesis in all cells:
Clozapine
Ethosuximide
Methotrexate
Procainamide
Methotrexate
Defined as exogenous agents that may have an adverse effect on a living organism; this term is more often used to describe environmental chemicals or drug exposures:
Poisons
Toxins
Xenobiotics
Xenobiotics
Agents that have an adverse effect on a biological system; this term is more often used when describing animal, plant, mineral, or gas:
Poisons
Toxins
Xenobiotics
Poisons
Most sensitive organ to ethanol toxicity:
Brain
Heart
Kidney
Liver
Liver
A AST/ALT ratio of greater than _____ is highly specific for ethanol-related liver disease
Greater than 0.5
Greater than 1.0
Greater than 1.5
Greater than 2.0
Greater than 2.0
Also known as rubbing alcohol:
Butyl alcohol
Ethyl alcohol
Isopropyl alcohol
Methyl alcohol
Isopropyl alcohol
Carbon monoxide expresses its toxic effects by causing a leftward shift in the oxygen–hemoglobin dissociation curve, resulting in:
Decrease amount of oxygen delivered to tissue
Increase amount of oxygen delivered to tissue
Variable amount of oxygen delivered to tissue
Normal amount of oxygen delivered to tissue
Decrease amount of oxygen delivered to tissue
Only treatment for carbon monoxide poisoning:
Corticosteroids
Intravenous immunoglobulins
Platelet transfusion
100% oxygen therapy
100% oxygen therapy
Overdose of acetaminophen is associated with a severe:
Nephrotoxicity
Hepatotoxicity
Ototoxicity
Neurotoxicity
Hepatotoxicity
An illicit amphetamine derivative that is commonly referred to as “ecstasy”
Amphethamine
Cannabinoid
Metamphetamine
Methylenedioxymethylamphetamine
Methylenedioxymethylamphetamine
Half-life of ecstasy:
0.5 to 1 hour
1 to 2 hours
7 to 8 hours
8 to 9 hours
8 to 9 hours
Half-life of ecstasy: 8 to 9 hours
Half-life of THC: 1 day after a single use and 3 to 5 days in chronic, heavy consumers
Half-life of cocaine: 0.5 to 1 hour
Half-life of benzoylecgonine: 4 to 7 hours
Half-life of cocaine:
0.5 to 1 hour
1 to 2 hours
7 to 8 hours
8 to 9 hours
0.5 to 1 hour
Half-life of ecstasy: 8 to 9 hours
Half-life of THC: 1 day after a single use and 3 to 5 days in chronic, heavy consumers
Half-life of cocaine: 0.5 to 1 hour
Cocaine’s short half-life is a result of rapid hepatic hydrolysis to inactive metabolites.
Half-life of benzoylecgonine: 4 to 7 hours
All of the following are naturally occurring opiates, except:
Codeine
Heroin
Morphine
Opium
Heroin
OPIATES:
The naturally occurring substances include opium, morphine, and codeine.
Heroin, hydromorphone (Dilaudid), and oxycodone (Percodan) are chemically modified forms of the naturally occurring opiates.
Meperidine (Demerol), methadone (Dolophine), propoxyphene (Darvon), pentazocine (Talwin), and fentanyl (Sublimaze) are the common synthetic opiates.
Environmental pollutants:
Elemental mercury
Mercurous mercury
Mercuric mercury
Alkyl mercury
Alkyl mercury
In contrast to elemental and inorganic mercury, organic mercury com- pounds, containing alkyl, aryl, and alkoxyalkyl moieties, are environmental pollutants.
Which specimen is the sample of choice for lead screening?
Whole blood
Serum
Urine
Hair
Whole blood
Lead accumulates in RBCs, bones, and neural tissues, and whole blood, hair, and urine are suitable for demonstrating lead toxicity.
Greatest sensitivity is obtained by using whole blood, which can detect exposure over time.
When measuring trace metals in blood other than lead, what type of tube should be used?
Navy blue top
Green top
Purple top
Red top
Navy blue top
In order to avoid trace contamination by metals present in the stopper lubricants, a tube with a navy blue top is used for measuring trace metals.
Tubes with tan stoppers containing EDTA are used for lead assay because they are certified to contain no more than 0.25 μg/dL lead.
