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Pharmacodynamics Flashcards

7 cards from real Pharmacology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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

    Answer: Lower potency but equal efficacy compared to morphine

    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.

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

    Answer: Cytokine/growth factor receptors

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

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

    Answer: Additive effect

    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.

  4. Spare receptors (receptor reserve) exist when:

    Answer: Maximal effect is achieved with less than full receptor occupancy

    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.

  5. Phenoxybenzamine is an example of which type of antagonist?

    Answer: Irreversible (non-competitive) antagonist

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

  6. The Hill equation describes the relationship between drug concentration and effect. A Hill coefficient (n) greater than 1 indicates:

    Answer: Positive cooperativity in ligand binding

    A Hill coefficient >1 indicates positive cooperativity, meaning binding of one drug molecule increases the affinity of subsequent binding, producing a steeper sigmoidal dose-response curve.

  7. Which second messenger is generated when Gq-coupled receptors are activated?

    Answer: Inositol trisphosphate (IP3) and diacylglycerol (DAG)

    Gq proteins activate phospholipase C-β, which cleaves PIP2 into IP3 (triggering intracellular Ca2+ release) and DAG (activating protein kinase C).