Vocab Flashcards
1
Q
Agonist
A
- A drug that activates a receptor by binding to that receptor.
- Most agonists bind through a combination of ionic, hydrogen, and Van Der Waals interactions, which makes them reversible.
2
Q
Antagonist
A
- A drug that binds to the receptor without activating the receptor.
- Most antagonists bind through a combination of ionic, hydrogen, and Van Der Waals interactions, which makes them reversible.
- Antagonists block the action of the agonist by simply getting in the way of the agonist, preventing the agonist from binding to the receptor and producing the drug effect.
- These drugs get in the way of the agonist.
3
Q
Competitive antagonism
A
- Is present when increasing concentrations of the antagonist progressively inhibit the response to the agonist.
- This causes a rightward displacement of the agonist dose-response curve/ relationship.
4
Q
Non-competitive antagonism
A
- Is present when, after administration of an antagonist, even high concentrations of an agonist cannot completely overcome the antagonism.
- In this instance, either the antagonist is bound irreversibly/ covalently to the receptor site, or it binds to a different site on the molecule and the interaction is allosteric (occurring at another site that fundamentally alters the activity of the receptor).
- This type of antagonism causes both a rightward shift of the dose-response relationship as well as a decreased maximum efficacy of the concentration versus response relationship.
5
Q
Partial agonist
A
- A drug that binds to a receptor (usually at the agonist site) where it activates the receptor but not as much as a full agonist.
- Even at supramaximal doses, a partial agonist cannot cause the full drug effect.
- When a partial agonist is administered with a full agonist, it decreases the effect of the full agonist and acts like an antagonist.
- EX: Butorphanol acts as a partial agonist to the mu-opioid receptor. When given alone, it is a modestly efficacious analgesic. When given with fentanyl, it will partly reverse the fentanyl analgesia.
6
Q
Inverse agonist
A
- A drug that binds at the same site as the agonist (and is likely to compete with the agonist), but they produce the opposite effect of the agonist.
- Inverse agonists turn off the constitutive activity of the receptor.
- The inverse agonist favors the inactive state of the receptor.
- Can be classified as an antagonist.
- EX: propranolol, metoprolol, cetirizine, loratadine, naloxone
7
Q
Tolerance
A
- A person’s diminished response to a drug over a long course of the drug’s exposure at a certain dose.
- This mechanism allows the body’s physiological processes to adapt to a constantly changing environment.
8
Q
Pharmacokinetics
A
- The quantitative study of the absorption, distribution, metabolism, and excretion of injected and inhaled drugs and their metabolites.
- Pharmacokinetics describes what the body does to the drugs.
9
Q
Central volume
A
- The volume that an intravenously injected drug initially mixes into.
- This is the volume where we inject our intravenous drugs and also the volume we measure when we draw blood samples. The other volumes are peripheral volumes of distribution.
10
Q
Vessel rich group
A
- Following a bolus injection, the drug initially goes to the tissues that receive the bulk of arterial blood flow, which are the brain, heart, kidneys, and liver.
- These tissues are often called the vessel-rich group.
- The rapid blood flow to these highly perfused tissues ensures that the tissue drug concentration rapidly equilibrates with arterial blood.
11
Q
Zero order processes
A
- A drug elimination pathway where a constant amount of drug is eliminated per unit time, regardless of the current drug concentration in the body.
- This means the rate of elimination remains constant even as the drug level decreases.
- The consumption of oxygen and the production of carbon dioxide are processes that happen at a constant rate called zero-order processes.
- The rate of change for a zero-order process is dx/dt=k.
- This says that the rate of change is constant. If X represents the amount of drug and T represents time, then the units of K are amount/time.
12
Q
First order processes
A
- A process where a constant proportion (percentage) of a drug is eliminated from the body per unit time.
- This means that the rate of elimination is directly proportional to the drug concentration, so as the drug concentration increases, the rate of elimination also increases.
- This is the primary elimination model for most medications.
- A process that occurs at a rate proportional to the amount.
- The rate of change is slightly more complex in a first-order process than in a zero-order process. Here, dx/dt=KxX.
- In this equation, X has units of amount, so the units of K are 1/time.
- In pharmacokinetics, K is negative because concentrations decrease over time.
13
Q
Elimination half time
A
- Ke0 is the rate constant for the elimination of a drug from the effect site.
- It is most easily understood in terms of its reciprocal 0.693/Ke0, the half-time for equilibration between the plasma and the site of drug effect.
14
Q
Elimination half life
A
- The time it takes for the concentration of the drug in the plasma or the total amount in the body to be reduced by 50%.
- After 1 half-life, the concentration in the body will be ½ of the starting dose.
15
Q
Context sensitive half time
A
- This is the time for the plasma concentration to decrease by 50% from an infusion that maintains a constant concentration.
- The context-sensitive half-time increases with longer infusion durations because it takes longer for the concentrations to fall if the drug has accumulated in the peripheral tissues.
- It can also be described as the time it takes for a drug’s plasma concentration to decrease by 50% after a continuous infusion has stopped.
- “Context” refers to the duration of the infusion, meaning the half-time can vary depending on how long the drug was infused for.
16
Q
clearance
A
- The amount of blood completely cleared of a drug per unit time.
- The clearance for drugs permanently removed from the central compartment is the “systemic clearance”, so named because it is the process that clears the drug from the entire system.
- Clearance does not change with dose, concentration, time, or anything else.
- When clearance is constant, the pharmacokinetics are said to be linear (proportional) because a linear increase in dose results in a linear increase in concentration.
- If you double the dose, you double the concentration.
17
Q
Pharmacodynamics
A
- The study of the intrinsic sensitivity or responsiveness of the body to a drug and the mechanisms by which these effects occur.
- The quantitative study of the body’s response to a drug.
- Pharmacodynamics describes what the drug does to the body.
18
Q
Stereochemistry
A
- The study of how molecules are studied in 3 dimensions.
19
Q
Chirality
A
- A unique subset of stereochemistry.
- The term chiral is used to designate a molecule that has a center of 3-dimensional asymmetry.
- This kind of molecular configuration is almost always a function of the unique tetrahedral bonding characteristics of the carbon atom.
- Nearly every building block in biology is chiral, as are the resulting proteins, sugars, and lipids.
20
Q
Enantiomerism
A
- Chirality is the structural basis of Enantiomerism.
- Enantiomers are a pair of molecules existing in 2 forms that are mirror images of one another but cannot be superimposed.
- EX: a right and left glove.
- In every other aspect, enantiomers are chemically identical.
- A pair of enantiomers is designated by the direction in which they rotate polarized light in solution.
- If the rotation is clockwise, then it is the D or + enantiomer, and if they rotate counterclockwise, then it is the L or – enantiomer.
- Enantiomers can exhibit differences in absorption, distribution, clearance, potency, and toxicity.
- Enantiomers can even antagonize the effects of one another.
21
Q
Racemic
A
- When the two enantiomers are present in equal proportions (50:50), they are referred to as a racemic mixture.
- A racemic mixture does not rotate polarized light (actually because it rotates light equally in clockwise and counterclockwise directions, these effects cancel each other out so that light is not rotated).
22
Q
Pharmacogenetics
A
- Describes genetically determined disease states that are initially revealed by altered responses to specific drugs.
- Examples of diseases that are unmasked by drugs include:
- atypical cholinesterase enzyme revealed by prolonged neuromuscular blockade after administration of succinylcholine or mivacurium,
- malignant hyperthermia triggered by succinylcholine or volatile anesthetics,
- glucose-6-phosphate dehydrogenase deficiency in which certain drugs cause hemolysis,
- intermittent porphyria in which barbiturates may evoke an acute attack.
23
Q
Amnesia
A
- A loss of memory that can be caused by certain drugs such as sedatives and hypnotics.
- Amnesia can be temporary or permanent and can affect the ability to recall events from the past or form new memories.
24
Q
Recall
A
- When a patient remembers events that happened during surgery while under general anesthesia.
- This may involve hearing sounds or conversations, feeling pain, being unable to move or breathe, and experiencing emotional distress.
- The incidence of conscious recall of intraoperative events is rare.
25
Q
Sedation (3 depths)
A
- The three depths of sedation are minimal, moderate, and deep.
- Minimal sedation is also known as anxiolysis and produces a relaxed state where the patient is awake and able to respond to verbal commands.
- Moderate sedation is also known as conscious sedation and produces a depressed state where the patient can respond to verbal commands and light touch and breathing and cardiovascular function are maintained.
- Deep sedation produces an unconscious state where the patient can only be aroused with repeated or painful stimuli and breathing may be impaired and may need to be supported.
26
Q
General anesthesia
A
- A state of unconsciousness and loss of feeling caused by drugs called anesthetics.
- It is used to keep patient’s pain-free during surgery and other procedures.
- Drug-induced unconsciousness.
27
Q
Analgesia
A
- The absence of pain or the relief of pain without loss of consciousness
28
Q
Allodynia
A
- The perception of pain sensations in response to normally nonpainful stimuli.
29
Q
Hyperalgesia
A
- Increased pain sensations to normally painful stimuli.
- When tissue injury and inflammation activate a cascade of events leading to enhanced pain in response to noxious stimuli.
- It is a leftward shift of the stimulus-response function that relates the magnitude of pain to stimulus intensity.
- Hyperalgesia is a consistent feature of somatic and visceral tissue injury and inflammation.
30
Q
Sensitization
A
- A phenomenon where repeated exposure to a drug elicits progressively increasing behavioral, neurocircuit, or neurotransmitter response to that same drug.
- Sensitization of nociceptors refers to their increased responsiveness to heat, cold, mechanical, or chemical stimulation that gives rise to primary hyperalgesia to these stimuli.
31
Q
Neuropathic pain
A
- Characterized by a reduced nociceptive threshold, persists in the absence of a stimulus, and is refractory to traditional analgesics.
- Injury of peripheral nerves by trauma, surgery, or disease such as diabetes frequently results in the development of neuropathic pain.
32
Q
Somatic pain
A
- Easily localized pain and characterized by distinct sensations.
33
Q
Visceral pain
A
- Diffuse pain and poorly localized.
- Visceral pain is typically referred to somatic sites, and it is usually associated with stronger emotional and autonomic reactions.
- Visceral pain is often produced by stimuli different from those adequate for the activation of somatic nociceptors.
34
Q
Neuralgia
A
- A type of nerve pain that feels like a sharp, shocking pain that follows the path of the nerve.
- It is caused by damage or irritation to a nerve.
35
Q
Tachyphylaxis
A
- The continued or repeated exposure to a drug that may lead to a weakened pharmacologic response.
- This presumed to be a consequence of diminished receptor sensitivity in response to consistent stimulation by a drug agonist, which produces a diminished pharmacological response in consequence.
36
Q
Additive
A
- When the combined effect of two or more drugs is the same as their individual effects.
- This is the most common type of interaction between drugs.
- EX: two vaccines that don’t interfere with each other can be combined into one shot.
37
Q
Synergistic
A
- When two or more drugs produce a greater effect when combined than when given separately.
- Can be harmful with things like drinking alcohol with depressants like valium or Xanax because it can increase depression.
38
Q
Efficacy
A
- A measure of the intrinsic ability of a drug to produce a given physiologic or clinical effect.
- Efficacy refers to the position of the concentration versus the response curve in the Y-axis.
- 2 drugs may have the same C50 (the concentration associated with 50% of the peak drug effect) but different efficacies.
39
Q
Potency
A
- 50% of the maximal effect of a full agonist.
- Potency refers to the relative drug concentration for a particular response on the Y-axis.
40
Q
Median effective dose (ED50)
A
- a. The dose of a drug required to produce a specific desired effect in 50% of individuals receiving the drug.
41
Q
Median Lethal dose (LD50)
A
- The dose of a drug required to produce death in 50% of patients (only tested on animals) receiving the drug.
42
Q
Therapeutic index
A
- a. The ratio between the LD50 and the ED50.
- TI = LD50/ED50.
- The larger the therapeutic index of a drug, the safer the drug is for clinical administration.
- Anesthetics have very narrow therapeutic windows.
43
Q
Acute pain
A
- Short-term pain.
- When pain receptors no longer detect any tissue damage, the pain sensation will stop.
- Acute pain does not persist after the initial injury has healed.
44
Q
Chronic pain
A
- Persistent pain beyond the expected period of healing.
- In this case, pain receptors continue to fire even in the absence of tissue damage.
- There may no longer be a physical cause of pain, but the pain response is still there.
