Pharmacology Pharmacodynamics 3

Question 1

A drug produces the same maximum effect as morphine but requires a 10-fold higher dose. This drug has:

Accepted Answer

Lower potency but equal efficacy compared to morphine

Answer

Potency refers to the dose required for a given effect; since this drug requires more drug for the same Emax, it is less potent but equally efficacious.

Question 2

Which receptor type uses a JAK-STAT intracellular signaling pathway?

Accepted Answer

Cytokine/growth factor receptors

Answer

Cytokine receptors (e.g., for interferons, erythropoietin) lack intrinsic kinase activity but associate with Janus kinases (JAKs) that activate STAT transcription factors.

Question 3

When two drugs are combined and the effect equals the sum of their individual effects, this is called:

Accepted Answer

Additive effect

Answer

An additive effect occurs when the combined effect of two drugs equals the arithmetic sum of their individual effects, as if each drug contributes independently.

Question 4

Spare receptors (receptor reserve) exist when:

Accepted Answer

Maximal effect is achieved with less than full receptor occupancy

Answer

Spare receptors exist when Emax is reached at concentrations that occupy only a fraction of available receptors, meaning receptor number exceeds what is needed for maximum response.

Question 5

Phenoxybenzamine is an example of which type of antagonist?

Accepted Answer

Irreversible (non-competitive) antagonist

Answer

Phenoxybenzamine covalently and irreversibly alkylates alpha-adrenergic receptors, permanently blocking them and reducing Emax rather than just shifting the dose-response curve.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Pharmacodynamics 3