Pharmacology Quiz: Receptors and Ligands

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What is the primary requirement to maintain a target concentration of a drug in the body?

The drug must be delivered at the same rate it is exiting the body (correct)

The drug must be administered at a rate proportional to the patient's weight

The drug must be administered at a constant rate

The drug must be administered at a rate inversely proportional to the patient's age

What is the condition required for the maintenance infusion rate equation to be applicable?

The drug has been administered for several hours

The peripheral tissues have fully equilibrated with the plasma (correct)

The patient must be anesthetized

The drug has reached its peak effect

What happens to the maintenance infusion rate if the peripheral tissues have not fully equilibrated with the plasma?

It is not affected

It underestimates the infusion rate (correct)

It remains the same

It overestimates the infusion rate

What is the time required for the peripheral tissues to fully equilibrate with the plasma?

Several hours Signup and view all the answers

What is the relationship between the maintenance infusion rate and the rate at which the drug is exiting the body?

They are equal Signup and view all the answers

What is the purpose of calculating the maintenance infusion rate?

To maintain a target concentration of the drug Signup and view all the answers

What is the limitation of using Vdpe to calculate the maintenance infusion rate?

It is not suitable for drugs with rapid plasma-effect site equilibration Signup and view all the answers

Why is the infusion rate higher initially after a bolus injection?

To replace the drug taken up by peripheral tissues Signup and view all the answers

What happens to the net flow of drug into peripheral tissues over time?

It decreases over time Signup and view all the answers

What is the equation to maintain the desired concentration after a bolus injection?

EQUATION 2.31 Signup and view all the answers

What happens to the infusion rate required to maintain the desired concentration over time?

It decreases over time Signup and view all the answers

What is the infusion rate at equilibrium (t = ∞)?

CT · Cl Signup and view all the answers

What happens to the plasma concentration after the bolus up to the time of peak effect?

It decreases as a result of dilution into a larger volume Signup and view all the answers

What is the characteristic of the equilibration between the plasma and the effect site at the time of peak effect?

The plasma and effect site concentrations are the same Signup and view all the answers

What is the symbol for the apparent volume of distribution at the time of peak effect?

Vdpe Signup and view all the answers

What is the equation that can be used to calculate the dose that provides the desired peak effect site concentration?

Dose = Cpe / Vdpe Signup and view all the answers

What is the Vdpe for fentanyl?

75 L Signup and view all the answers

How much fentanyl is required to produce a peak effect site concentration of 2 ng/mL for a typical patient?

150 μg Signup and view all the answers

What is the outcome of prolonged treatment of asthma with a β-agonist?

Decrease in the number of β-adrenergic receptors Signup and view all the answers

What type of receptors do opioids interact with?

Membrane-bound receptors Signup and view all the answers

What is the response to succinylcholine in lower motor neuron injury?

Exaggerated response Signup and view all the answers

What is the result of receptor upregulation or downregulation in response to specific stimuli?

Maintenance of homeostasis Signup and view all the answers

What is the classification of receptors based on?

Location Signup and view all the answers

What is the mechanism that contributes to variability in response to drugs?

Changing receptor numbers Signup and view all the answers

What is the primary measure represented on the x-axis in a concentration versus response curve?

Drug exposure Signup and view all the answers

What is the term that describes the position of the curve along the x-axis in a concentration versus response curve?

Potency Signup and view all the answers

What type of response can be measured on the y-axis in a concentration versus response curve?

Absolute, normalized, population, or physiologic responses Signup and view all the answers

What is the name of the equation that describes the relationship between drug exposure and response?

Hill equation Signup and view all the answers

What is the term that describes the dose that produces a 50% response?

Median effective dose Signup and view all the answers

What is the term that describes the ratio of the median lethal dose to the median effective dose?

Therapeutic index Signup and view all the answers

What is the effect of propofol on the GABAA receptor?

Increases the sensitivity to GABA Signup and view all the answers

What is the role of pharmacokinetics in drug action?

Describes what the body does to the drug Signup and view all the answers

What is the effect of ketamine on the N-methyl-D-aspartate (NMDA) receptor?

Decreases the activity of the NMDA receptor Signup and view all the answers

What is the difference between pharmacokinetics and pharmacodynamics?

Pharmacokinetics studies the drug's action, while pharmacodynamics studies the body's response Signup and view all the answers

What is the result of opioid binding to the μ-opioid receptor?

Triggers a chain reaction, activating an inhibitory G protein Signup and view all the answers

What determines the concentration of a drug in the plasma or at the site of drug effect?

Pharmacokinetics Signup and view all the answers