Exam 1 Flashcards
List three most important properties of drugs. Which is most important?
Effectiveness, safety, selectivity.
Effectiveness is most important
What does selectivity mean?
Produces only desired responses for which it is given.
List three types of drug names. Which is the best for communicating between health professionals?
Chemical, generic, trade.
Generic name is the best
What factor primarily determines drug concentration at the receptor?
Administration
Pharmacokinetics determines what?
How much a drug reaches the sites of action
List four processes of pharmacokinetics
Absorption, distribution, metabolism, excretion. (ADME)
How does changing the route from intravenous to oral influence dosage?
Oral dosages are usually higher than intravenous dosages, because there is a barrier to absorption.
Pharmacodynamics refers to what action?
The nature and intensity of response at its site of action.
Name the six rights of safe medication administration.
Right patient, right drug, right dose, right route, right time, right documentation.
Explain the difference between a contraindication and precaution
A contraindication prevents the drug use under all but the most severe circumstances.
A precaution increases the likelihood of an adverse reaction, but not a life-threatening one.
The Federal Food, Drug, and Cosmetic Act of 1938 resulted in what mandate?
Testing for toxicity
The Harris-Kefauver Amendment of 1962 mandated what two requirements?
Proof of effectiveness and rigorous testing procedures.
The Controlled Substances Act of 1970 identified drugs with a potential for what?
What was developed?
Potential for abuse.
Developed Schedules I-V
Schedule I includes what types of drugs? Schedule II?
Schedule I - drugs with no acceptable medical use and high abuse potential. Eg. Heroin, marijuana, etc.
Schedule II - drugs with therapeutic use, but high abuse potential. Eg. Oxycodone, Fentanyl, etc.
The FDA Amendments Act (FDAAA) of 2007 allowed the FDA oversight over what?
Safety oversight over drugs that had been approved. Specifically gave the FDA the authority to require post marketing safety studies, labeling changes to include new safety information, and restricting the distribution of drugs with safety concerns.
What does “off label” mean?
Taking a drug approved by the FDA for as different reason. The FDA did not approve it for this alternative case.
The Randomized Controlled Trial (RCT) requires what three features in drug testing?
Controls, randomization, blinding
Preclinical testing of a drug is done on whom?
Animals
List the four phases of clinical testing and identify the sample and goal. Which is post-marketing?
Phase I - healthy volunteers, evaluation of drug metabolism, pharmacokinetics, and biologic effect.
Phase II & III - patients, therapeutic use and dosage, safety and effectiveness
Phase IV - patients, post marketing surveillance of a large population
Define an adverse drug reaction
Any noxious, unintended, and undesired effect that occurs at NORMAL drug doses.
List 4 risk factors for adverse drug reactions.
Elderly, very young, severe illness, multiple drug use
Define side effect
A nearly unavoidable secondary drug effect produced at therapeutic doses.
Define allergic reaction.
An immune response triggered by a previous sensitizing administration.
Define toxicity.
An adverse drug reaction caused by excessive dosing.
Define idiosyncratic effect
An uncommon response resulting from a genetic predisposition.
Define paradoxical effect
Effect opposite of intended drug response
Define iatrogenic disease
A disease produced by a healthcare provider or by a drug
Define physical dependence
A state in which the body has adapted to prolonged drug exposure and will result in an abstinence syndrome if the drug is abruptly discontinued
Define teratogenic effect. When do most malformations occur?
The ability to cause a drug-induced birth direct. In the first trimester after implantation. (3-8 weeks)
List 5 symptoms of ototoxicity
- Deafness
- Dizziness
- Balance problems
- tinnitus
- headache
What is the main purpose of MEDWATCH?
Bring ADRs (adverse drug reaction) and product problems to light
What are 3 symptoms of anaphylaxis?
- Bronchospasm
- Laryngeal edema
- hypotension
What are Black Box warnings?
Concise summaries of adverse effects of concern in a box surrounded by a thick black line.
What are REMS?
REMS are risk evaluation and mitigation plans to minimize drug-induced harm
Define pharmacokinetics
The study of drug movement throughout the body
The cell membrane is composed of what?
A double layer of molecules known as phospholipids
Name two ions that which can pass through channels or pores.
Na+
K+
Define transport system. Is it selective or nonselective?
A system which transports drugs from one side of a cell membrane to another. Only carries drugs with a particular structure
What type of drug can penetrate a cell membrane?
Lipophilic or lipid-soluble
List two types of non-lipid soluble drugs
Polar molecules and most ions
Define polar molecule. They dissolve well in what solvent?
Molecules which have an unequal or uneven distribution of electrons yet no net charge.
- Water
Explain ion trapping or pH partitioning
When there is a pH gradient between two sides of a cell membrane, acidic drugs will ionize and stay on the basic side.
Basic drugs will ionize and stay on the acidic side. Ionized drugs do not cross cell membranes.
Define absorption
The movement of drug from its site of administration into the blood .
What types of drugs are absorbed rapidly through the cell membrane?
Lipophilic or lipid-soluble
Delayed gastric emptying may delay the absorption of a drug meant to be absorbed where?
Intestines.
Parenteral drugs refer to routes of administration where?
Outside the GI tract
What is the barrier to intramuscular absorption
Capillary wall
What types of drugs are absorbed from intramuscular and subcutaneous sites?
Poorly soluble drugs (water-soluble)
Define bioavailability
drugs contain the same amount of identical chemical compound and are absorbed at the same rate and to the same extent
What is the most common mechanism by which drugs enter a cell?
direct penetration of the membrane
Should enteric-coated drugs be crushed? why/why not?
No, the drug would interact with stomach acids
What does the p-glycoprotein do?
It is a transmembrane protein which transports drugs out of the cells back into the blood stream or into lumens such as renal tubules or intestinal lumens.
What is a quaternary ammonium compound?
It is a compound with at least one nitrogen atom which has four bonds rather than three bounds. It has a positive charge and is unable to cross most membranes.
How long should a drug be administered intravenously to ensure the lowest serum concentration of the drug in the circulation?
Over one minute to fully distribute drug within entire blood volume.
Define pharmacodynamics
study of what drugs do to the body and how they do it
Discuss the three phase of the dose-response curve
Phase 1 - no measurable response
Phase 2 - increased dose increases response
Phase 3 - no further increase in response
Define maximal efficacy
Largest effect which can be produced by a drug
Define relative potency
Amount of drug needed to produce an effect. A potent drug produces effects at low doses.
The binding of a drug to a receptor does what to body processes?
Turns processes on or off
How does a cell membrane-embedded enzyme work?
Binding to the receptor on the cell membrane activates an enzyme inside the cell
How do ligand-gated ion channels work?
Binding to the receptor on the cell membrane activates ion channels
How do G protein–coupled receptors work?
Binding to the receptor activates the G protein which activates the effector
Where are transcription factors found? How do they work?
On the DNA in the cell.
Activate transcription of messenger RNA to make protein.
Which type of receptor is the fastest?
Ligand-gated ion channels
Explain the simple occupancy theory of drug-receptor interaction
The intensity of the response is determined by the number of receptors occupied
Define affinity
The strength of attraction between drug and receptor
Define intrinsic activity
The ability of the drug to activate a receptor upon binding
Define agonist
Drugs which bind to the receptor and mimic the action of endogenous regulatory molecules
Explain the actions of full and partial agonists
Full agonists have high intrinsic activity and produce a full effect. Partial agonists have a moderate intrinsic activity and produce a partial effect.
Define antagonists
Drugs which bind to the receptor and block the action of endogenous regulatory molecules
Explain the difference between competitive and noncompetitive antagonists
Competitive antagonists bind reversibly, and a maximal response can be achieved by increasing the concentration of the agonist. Noncompetitive antagonists bind irreversibly, and the maximal response cannot be achieved.
Explain up and down regulation
Down regulation includes decreasing the number of receptors &/or response. Up regulation includes increasing the number of receptors &/or response
List three receptorless drugs
Antacids, antiseptics, saline laxatives
Define the average effective dose
Dose producing a therapeutic response in 50% of the population
Define the therapeutic index. Is a large index safer or more dangerous?
The ratio of the lethal dose to the average effective dose. Safer
What is the relationship between the number of drugs a patient takes and the risk of drug-drug interactions?
The more drugs the patient takes, the higher the risk of drug-drug interaction
List three types of drug-drug ineractions
Potentiative, inhibitory, unique
How many laxatives affect absorption?
Laxatives can decrease absorption by increasing drug passage.
Decreasing cardiac output may do what to drug excretion?
Decrease drug excretion
What organ system is responsible primarily for drug metabolism?
Liver
What happens to drug levels of drug metabolized by the P450 system when the system is inhibited? Induced?
When metabolism is inhibited in the P450 pathway, drugs being metabolized by that pathway are not metabolized as rapidly and plasma drug levels increase. Conversely, when the system is induced, metabolism of those drugs occurs more rapidly, decreasing plasma drug levels.
What 4 processes happen with the induction of PGP (P-Glycoprotein)?
Decreased intestinal absorption, decreased fetal exposure, decreased brain exposure, increased elimination of drugs into bile or urine
Calcium may do what to the absorption of tetracycline?
Decrease absorption
How does grapefruit affect the absorption of drugs from the intestines? How long does grapefruit exert this effect?
Grapefruit inhibits CYP3A4 metabolism in the intestinal wall for 72 hours, so more drug is absorbed. The serum level of the drug increases.
How would you administer a drug on an empty stomach?
1 hr before or 2 hrs after a meal
What is the blood-brain barrier? Name two ways drugs enter the brain.
The capillaries of the brain do not have gaps between the cells of the capillaries. Drugs must pass through the cell membrane or be transported by a transport system.
The cytochrome P450 system refers to a family of enzymes which does what?
Metabolize drugs
Kidneys are unable to excrete what type of drugs?
Highly lipid-soluble
Define prodrug.
An inactive compound which can be converted into an active drug
Define the first-pass effect.
Blood passes through the liver before reaching the systemic circulation
How do hepatic inducers affect the rate of drug metabolism?
Increases
If a drug binds to albumin and displaces another drug from the site, what happens to the serum concentration of the drug displaced?
Increases
At what age does the infant’s liver develop into its fully capacity?
One year
The most important organ for drug excretion is what?
The kidneys
Which drugs remain in the urine for excretion?
Polar and ionized drugs
Define enterohepatic circulation
Drugs excreted in the bile are reabsorbed into the portal blood
What type of drugs easily enters breast milk?
Lipid-soluble or lipophilic
Define the minimum effective concentration (MEC)
The plasma drug level at which a drug has a therapeutic effect
Define toxic concentration
The plasma drug level at which toxic effects begin
Define therapeutic range
The range of plasma drug levels that fall between the MEC and the toxic concentration
Define duration
The length of time the drug is in the therapeutic range
Define half-life
The time required for the amount of drug in the body to decrease by 50%. For example, if the half-life is one day, in 1 day, 50% is left; in 2 days, 25% is left; in 3 days, 12.5% is left; etc.
How many half-livers does it take to clear a drug from the body? What about the half lives of metabolites?
4 half-lives
Some metabolites may have longer half-lives than the drug itself
Define plateau. What is the relationship between absorption and elimination?
Steady concentration of drug reached after repeated doses
Absorption = Elimination
Why are loading doses given?
To shorten the time to plateau
Why are maintenance doses given?
To continue the plateau
