Pharmacodynamics Quiz

Pharmacodynamics: Understanding the Effects of Drugs on the Body

• Pharmacodynamics is the study of what a drug does to the body and how it interacts with drug targets.
• Drug targets are usually proteins such as receptors, ion channels, enzymes, or carriers.
• Drugs can function as agonists, mimicking the effects of endogenous molecules, or as antagonists, inhibiting the normal function of endogenous agonists.
• Competitive antagonists compete with agonists for the same binding site on receptors, while non-competitive antagonists bind to different sites and indirectly inhibit agonist binding.
• Inverse agonists inhibit the basal activity of receptors, even in the absence of endogenous agonists.
• The type 1 dose-response curve shows the relationship between drug dose and response efficacy, typically represented in a sigmoid log form.
• The maximal effect or Emax of a drug is its intrinsic activity, while maximal efficacy refers to the plateau of the dose-response curve.
• Full agonists have an intrinsic activity of 1 and can produce 100% of the desired effect, while partial agonists have an intrinsic activity between 0 and 1.
• Antagonists have an intrinsic activity of 0 and block the binding of endogenous agonists.
• Inverse agonists have a negative intrinsic activity and inhibit the basal activity of receptors.
• Affinity is the attractiveness of a drug to its receptor, while potency refers to the power of a drug at a specific concentration.
• Competitive antagonists shift the dose-response curve to the right, while non-competitive antagonists shift it down and decrease the maximum effect of the drug.
• Type 2 dose-response curves consider the number of subjects responding to a drug and can show therapeutic, toxic, and lethal responses.