1.1 Pharm Review

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Questions and Answers

What is the primary inhibitory neurotransmitter in the brain?

Dopamine

Glutamate

Serotonin

GABA (correct)

What does the efficacy of a drug refer to?

The duration of action of the drug

The maximal response when all receptor sites are occupied (correct)

The chemical composition of the drug

The route of administration for the drug

How is the primary mechanism of termination of action of a bolus dose of an anesthetic induction agent achieved?

Redistribution to the vessel intermediate group (correct)

Metabolism by the liver

Reabsorption into the central nervous system

Excretion through the kidneys

What does volume of distribution represent?

The dosage divided by the initial plasma concentration of the drug Signup and view all the answers

Which type of drugs activate the GABAA receptor?

Sedative-hypnotics Signup and view all the answers

Which measure is considered the best measure of renal function?

Glomerular filtration rate Signup and view all the answers

What is the most reliable measure of glomerular filtration rate?

Creatinine clearance Signup and view all the answers

What is a pharmacokinetic model that can adequately describe the pharmacokinetics of most anesthetic drugs?

Two or three compartment model Signup and view all the answers

What does the lag between peak plasma concentration and peak effect represent from a pharmacodynamic standpoint?

Hysteresis effect Signup and view all the answers

Which type of receptors bind an extracellular molecule (ligand) and convert this input into a change in intracellular behavior?

G protein-coupled receptors Signup and view all the answers

Which family of receptors acts through activation or inhibition of an enzyme, ion channel, or other target?

G protein-coupled receptors Signup and view all the answers

Which type of receptors are typically a tyrosine kinase that phosphorylates an intracellular second messenger?

Enzyme-linked transmembrane receptors Signup and view all the answers

What is the best measure for determining proper bolus dosing for a drug?

$V_dpe$ Signup and view all the answers

Which type of drug is poorly absorbed from the GI tract?

Ionized Signup and view all the answers

Where is the principle site of absorption for oral drug administration?

Small intestine Signup and view all the answers

Which route of administration bypasses the liver?

Oral transmucosal Signup and view all the answers

In which of the following does the slowest equilibration of a drug occur?

Bone Signup and view all the answers

Which compartment is the slowly equilibrating compartment?

Vessel poor group Signup and view all the answers

What is the primary mechanism of termination of action of a bolus dose of an induction agent?

Redistribution to other tissues Signup and view all the answers

What is the function of the apparent volume of distribution (Vd)?

Model to explain drug concentration in blood following a given dose Signup and view all the answers

Which of the following does not affect the volume of distribution of a drug?

Renal failure Signup and view all the answers

'Only free drug can cross cell membranes' - this statement refers to which phenomenon?

Protein binding effect on drug distribution Signup and view all the answers

'Most drugs are protein bound to some extent' - what reduces the concentration of plasma proteins?

Age Signup and view all the answers

Which type of receptor consists of a protein linked to 7 transmembrane spanning domains?

G protein-coupled receptor Signup and view all the answers

What results in a conformational change in the G protein-coupled receptor, allowing substitution of GTP for GDP on the Gα protein?

Ligand binding Signup and view all the answers

Which neurotransmitter acts as the primary excitatory neurotransmitter in the central nervous system and is important in learning, memory, and central pain transduction?

Glutamate Signup and view all the answers

Which ion channel opens when ions flow in or out based on their concentration gradients?

Ligand-gated ion channel Signup and view all the answers

Entry of which ion inhibits the cell?

$Cl^-$ Signup and view all the answers

Which type of receptor is associated with rapid synaptic transmission, synaptic plasticity, and long-term potentiation?

NMDA receptors Signup and view all the answers

What activates the Gα protein which then activates or inhibits an enzyme, ion channel, or other target?

$GTP$ binding Signup and view all the answers

What characterizes an agonist according to the receptor theory?

Maximal response when all receptor sites are occupied Signup and view all the answers

What is the defining factor for potency according to the receptor theory?

Defined by the dose needed to produce a defined effect Signup and view all the answers

Which type of antagonist can be overcome by large doses of agonist?

Competitive antagonist Signup and view all the answers

What is the main difference between partial and full agonists?

Partial agonists favor an active state less than full agonists Signup and view all the answers

In pharmacokinetics, what does the term 'volume of distribution' refer to?

The distribution of a drug in various body tissues Signup and view all the answers

Which type of drugs come in an acidic solution to render them more water soluble?

Basic drugs Signup and view all the answers

What does $pKa - pH$ indicate when it's a negative number for weak bases?

Less than 50% of the drug is protonated (ionized) Signup and view all the answers

Which enzyme is responsible for the metabolism of the majority of drugs?

CYP3A4 Signup and view all the answers

Which phase of drug metabolism increases the drugs polarity preparing it for phase II reactions?

Phase I reactions Signup and view all the answers

What is the formula for hepatic extraction ratio (ER)?

ER = Q x (Cinflow - Coutflow) Signup and view all the answers

Which type of drug metabolism is more affected by changes in liver blood flow?

Flow-limited metabolism Signup and view all the answers

Which drug is categorized as a low hepatic extraction ratio (HER) drug?

Diazepam Signup and view all the answers

Which process involves the passive reabsorption of water-soluble drugs from the tubules?

Tubular reabsorption Signup and view all the answers

What is the formula for Calculated Creatinine Clearance?

(140-age) x lean body mass / Plasma creatinine concentration x 72 Signup and view all the answers

What is the main purpose of concentration-response relationships in pharmacodynamics?

To measure the dose required to produce a specific effect Signup and view all the answers

Which term describes the maximum effect a drug can produce?

Efficacy Signup and view all the answers

What is the therapeutic index of a drug?

The ratio of LD50/ED50 Signup and view all the answers

What is the main focus of response surface models?

The net effect of combining two drugs Signup and view all the answers

What does ED50 stand for in pharmacology?

The dose required to produce a specific effect in 50% of patients Signup and view all the answers

What is the time required for the drug concentration to decrease by 50% following termination of a steady state infusion?

Context-sensitive half-time Signup and view all the answers

Which mathematical technique is sometimes labeled non-compartmental and may avoid some of the confusion related to trying to perceive a compartment as specific tissues?

Stochastic dosing Signup and view all the answers

What do isoconcentration nomograms plot?

The plasma concentration achieved over time with various infusion rates Signup and view all the answers

What is used to compensate for distribution to peripheral tissues in the BET dosing scheme?

Decreasing rate over time Signup and view all the answers

What is the main consideration when determining the initial infusion rate in practice?

Clearance from the central compartment Signup and view all the answers

What is the primary mechanism for patient controlled sedation with propofol?

An infusion rate is established and patient demand dose increases the rate by a small amount. Signup and view all the answers

What is used to control drug delivery in closed-loop infusions for anesthetic purposes?

Output from the patient as processed EEG or auditory evoked potentials Signup and view all the answers

What does hysteresis/biophase refer to in combined pharmacokinetic/pharmacodynamic models?

The distribution of drug from effect site to less well-perfused tissues, and then ultimately back to the central compartment for clearance. Signup and view all the answers

Study Notes

Neurotransmitters

The primary inhibitory neurotransmitter in the brain is GABA (gamma-aminobutyric acid).
Glutamate serves as the primary excitatory neurotransmitter in the central nervous system, crucial for learning and memory.

Drug Mechanisms and Efficacy

Efficacy of a drug refers to its ability to produce a desired therapeutic effect.
GABAA receptors are activated by sedative-hypnotic drugs, benzodiazepines, and barbiturates.
Partial agonists produce a less than maximal response compared to full agonists at the same receptor.

Pharmacokinetics

The volume of distribution (Vd) represents the degree to which a drug spreads into body tissues.
The primary mechanism of termination for bolus doses of anesthetic induction agents is redistribution away from the site of action.
Renal function is best measured using creatinine clearance or estimated glomerular filtration rate (GFR).

Administration and Absorption

The principal site for oral drug absorption is the small intestine, where most nutrients and drugs are absorbed.
Drugs poorly absorbed from the gastrointestinal tract often include large molecules or those with poor solubility.
The intravenous route of administration bypasses the liver, leading to immediate bioavailability.

Drug Distribution and Compartment Theory

The slowly equilibrating compartment refers to areas where drug distribution occurs slower, often including fat tissues.
Volume of distribution impacts drug dosing and effectiveness; only free drugs can cross cell membranes to exert their effects.

Receptor Types and Functions

Receptors that bind extracellular ligands and trigger intracellular changes include ionotropic and metabotropic receptors.
G protein-coupled receptors are characterized by a protein linked to seven transmembrane domains.
Tyrosine kinase receptors, which phosphorylate intracellular messengers, are associated with growth factors.

Pharmacodynamics

The time lag between peak plasma concentration and peak effect reflects the pharmacodynamic response time.
Agonists activate receptors, while antagonists inhibit them; competitive antagonists can be overcome by increasing agonist concentrations.
The therapeutic index indicates drug safety, defined as the ratio of toxic dose to effective dose.

Drug Metabolism

Phase I metabolism modifies drug structures to increase polarity, preparing for Phase II reactions, which involve conjugation.
Cytochrome P450 enzymes are primarily responsible for metabolizing most drugs.
Low hepatic extraction ratio (HER) drugs are less affected by changes in liver blood flow.

Clinical Measurements

ED50 refers to the dose of a drug that produces 50% of its maximal effect.
Creatinine clearance is calculated using renal function formulas to assess kidney health.
Hysteresis in pharmacokinetic/pharmacodynamic models refers to the lag in drug effect compared to plasma concentration changes.

Drug Delivery Systems

Concentration-response relationships assess how the dose correlates with drug effects.
Patient-controlled analgesia with propofol allows patients to self-administer sedation effectively through closed-loop infusion systems.
BET dosing schemes adjust for distribution to peripheral tissues to optimize drug delivery.

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