Dynamics of Drug Actions Quiz

Which of the following terms describes the situation when a drug acting on one receptor increases the action of another drug acting on a different receptor?

A full agonist does not necessarily have the highest potency.

What is the term used to describe a rapid decrease in responsiveness to a drug after repeated administrations in quick succession?

The Graded-Dose-Response-Curve can be used to determine the proportion of the population that therapeutically responded or developed side effects to a drug.

Match the following terms with their corresponding definitions.

Which of the following is NOT a characteristic of a drug with a wide therapeutic window?

What is the term used to describe the state of a drug's effect being diminished or absent after repeated administration, and it cannot be overcome by increasing the drug concentration?

A full agonist is a drug that produces the maximal response possible for that receptor.

Dynamics of Drug Actions

Efficacy vs. potency are important for drug selection.
Comparing drug responses: Drugs acting on the same or different receptors.
Potentiation and antagonism are important in therapy.
Predicting drug safety is done using dose-frequency curves.

Graded Dose-Response Curve

Used to compare drug effects.
Comparing agonists: Some are full agonists (same efficacy as a standard), while others are partial agonists (less efficacy) and varying levels of potency
Potentiating an agonist (shift left): increases efficacy by altering efficacy curve.
Antagonizing an agonist (shift right): decreases efficacy.
Competitive reversible antagonism: decreases potency but can be overcome.
Competitive irreversible antagonism: or Non-competitive antagonism decreases efficacy that cannot be overcome.

Quantitative Comparison of Different Drugs

Comparing drugs acting on the same receptor.
Comparing drugs acting on different receptors. Effectiveness can vary.
Synergism (or summation): One drug enhances the other but not in the same receptor.

Quantal Dose-Response Curve

Used to predict drug safety:
- ED50: the dose that produces an effect in 50% of subjects
- TD50: the dose that causes a toxic effect in 50% of subjects
- Therapeutic index (TI): TD50 / ED50 A higher TI indicates a safer drug.
Therapeutic Monitoring: Blood drug monitoring is needed when drugs have narrow therapeutic windows.

Variation in Drug Response

Tolerance: Reduced response to a drug over time.
Tachyphylaxis: Rapidly developing tolerance.
Refractoriness: Loss of therapeutic efficacy.
Resistance (in treatment): Complete loss of effectiveness to antibiotics/anticancer.
Hypersensitivity: Increased response that can be dangerous.
Idiosyncrasy: Abnormal response to a drug due to genetic factors.
Hypersensitivity (allergy): An immune system reaction, to a drug.
Dependence: Adaptive state to repeated drug use with withdrawal symptoms when stopped. (Includes Addiction)

Test your knowledge on the dynamics of drug actions including efficacy versus potency, drug responses, and therapeutic antagonism. Explore concepts like graded dose-response curves and quantitative comparisons of different drugs. This quiz will help solidify your understanding of pharmacology principles crucial for drug selection and safety predictions.