Lecture 1: Basics of Pharmacology Flashcards
What is stereochemistry?
3D structural orientation of molecules
What are the two possible clinical responses of drugs?
Toxicity or effectiveness
What is a common tachyphylactic drug?
Ephedrine
Which type of drug (ionized or nonionized) is able to diffuse and equilibrate into other tissues?
Nonionized, though it may become ionized once it diffuses
Intravascular fluid is part of what compartment in the two compartment model?
Central compartment
What is biotransformation?
A chemical process where a drug is altered in the body
What are the two types of membrane receptors?
Agonists and antagonists
What is a racemic mixture?
A mixture that has equal parts left and right-handed enantiomers of a chiral molecule
The process by which drugs in the systemic circulation are converted into metabolites or exit the body
Elimination (Metabolism)
Which method of administering drugs would be represented by a graph that demonstrates a steep incline followed by a slow decay? Why is the decay progressively slower and slower?
Direct injection of drug into blood with route of elimination (think of a drain in a sink)
The slope becomes less and less steep because the level of volume in the blood falls as it is eliminated (“drained”), so the pressure gradient that drives the process of elimination becomes less and less (exponential decay curve)
What are three factors that lead to decreased amounts of plasma protein in the blood?
Age
Liver failure
Pregnancy
What is the average plasma volume?
3 L
In a pH higher than its pK, an acidic drug will be ionized or nonionized?
Ionized
What is the difference between pharmacological effect and clinical response?
Pharmacological effect occurs at the molecular level; clinical response is evident in the things we can measure via sight, touch, smell, hearing, smell, etc.
The term “parenteral” means that drugs are administered:
“aside from” the alimentary tract
Which type of receptor triggers a cascade when bound by a drug?
Enzyme receptor
Subcutaneous tissue lies below which level of skin?
Dermis
Ionized drug + nonionized drug: which type crosses cell membranes?
Nonionized drugs cross cell membranes.
A noncompetitive inhibitor of acetylcholinesterase would have what major side effects?
Build up Ach concentrations in the body with no relief; cause SLUDGE-BBM Salivation Lacrimation Urination Defecation GI distress Emesis Bronchoconstriction Bradycardia Miosis, Muscle spasm
Which type of channel involves a conformational shift to open a channel and let ions flow through?
Ligand-gated ion channel
What is tachyphylaxis?
An exhaustive situation in which after dosing a drug, you must administer a higher dose to get the same initial response
Drugs leave the systemic circulations and enter the tissues of the body via?
Distribution
How can the binding of a competitive antagonist be overcome?
Increase the concentration of the agonist at the receptor site
Which enantiomer of Bupivicaine is cardiotoxic? Which is not?
L-isomer is cardiotoxic.
R-isomer (Rhopivicaine) is not.
How do drugs effect voltage-gated ion channels?
Example?
They bind and block the channel so that ions cannot pass through to cell, altering the electrical activity of the cell.
Lidocaine and Na+ channels
What is the major converter of drugs to metabolites in the liver?
Cytochrine P450
What is an antagonist?
A drug that produces its clinical effect by binding to a receptor without activating it and simultaneously prevents an agonist from stimulating it
What type of antagonism cannot be overcome by increasing the concentration of the agonist?
Irreversible blockade
What are two ways drugs exit the central compartment in the compartment model?
Biotransformation + excretion
In the compartmental model, from the central compartment free drug can travel to what three areas of the body?
Therapeutic site of action (positive effects)
Tissue reservoirs
Unwanted site of action (negative effects)
In a pH lower than its pK, a basic drug will be ionized or nonionized?
Ionized
Which method of administering drugs would be represented by a graph that demonstrates a steep incline followed by a steep and then more gradual decline?
Most realistic model; takes into account both the elimination mechanism and extravascular equilibration. Rapid equilibration (steep decline) and then slower elimination (more gradual decline)
In the compartment model, we examine the pharmacokinetics of drugs in terms of:
What compartments they travel to + what happens when they reach those compartments
By what mechanism does the liver remove drug from plasma?
Hoffman elimination
In the central compartment, some drug is bound to:
proteins
In which compartment (central or peripheral) will lipophilic drugs tend to sequester?
Peripheral compartment; likes to cross cell membranes and remain in fatty tissues
Phenylephrine is an example of what kind of membrane receptor?
Agonist: stimulates sympathetic response on a-1 receptor
How many phases of metabolic biotransformation are there?
Two
What is a prodrug? Give an example.
A drug that itself is not an active effector, but once it is metabolized in the body, those metabolites are active effectors
Morphine itself isn’t active, but its metabolite morphine-6-glucoronite is active
Which type of drug (ionized or nonionized) is soluble in water?
Ionized
What are the four major types of reactions in metabolism?
1) Oxidation
2) Reduction
3) Conjugation
4) Hydrolysis
Interstitial fluid is a component of
Extracellular fluid, along with plasma
What is the R-isomer (type of enantiomer) of Bupivicaine?
Rhopivicaine
Phenylephrine is a/an ____________ -acting agonist. Its mechanism is:
directly-acting: binds to alpha and beta receptors to cause an effect
Why do patients feel hungover after having been administered thiopental as compared to propofol?
Longer elimination phase; hangs around in the body
Narcan is an ___________ of which membrane receptors?
Antagonist of opioid receptors
Drugs sequestered in tissues where they are ionized or nonionized?
Ionized; they freely travel in tissues where they are nonionized, but once they are ionized they cannot cross into other tissues
What occurs in phase II of metabolic biotransformation?
Polar metabolite conjugates with an endogenous substrate to become water soluble
What are the two components of extracellular fluid?
Plasma + Interstitial fluid
Drugs that are not distributed or eliminated go where? This marks the transfer from pharmacokinetics to?
Site of action; pharmacodynamics