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USMLE - Pharm
Kaplan Section 1 Chapter 2 Pharmacodynamics
Question | Answer |
---|---|
What are agonists? | Drugs that ACTIVATE receptors |
What are full vs. partial agonists? | Full agonists produce a maximal response. Partial agonists cannot and are less effective. |
Potentiation of an agonist shifts the dose-response curve to L or R? | Left |
Antagonism of an agonist shifts the dose-response curve to L or R? | Right |
What is the ED50? | The dose of a drug that is effective in 50% of the patient population |
A steep slope for a cumulative dose response curve means what? | There is little variability in drug response in a given population. The less steep the slope, the greater the variability in patient sensitivity to the effects of a drug. |
What is the TD50? | The dose that is toxic to 50% of the patient population. |
What is the LD50? | The dose that is lethal to 50% of the patient population. |
What is the therapeutic index? | Evaluates the relative safety of a drug. |
A drug with a lower therapeutic index means what? | That the doctor needs to be more careful in the dosing of the drug for a patient because there is only a small therapeutic window in terms of the dosing. |
What happens when an agonist binds to a Gs receptor? | activation of adenylyl cyclase --> increase in cAMP |
Mnemonic to remember the G-protein-coupled ANS receptors. | Kiss and kick til you're sick of sex. qiss qiq siq sqs = a1 a1 B1 B2, M1 M2 M3, D1 D2 H1, H2 V1 V2 |
What happens when Gi receptors are stimulated? | inhibition of adenylyl cyclase --> decrease in cAMP |
What happens when Gq receptors are stimulated? | activation of phospholipase C |
What happens when endothelial cells release NO? | NO --> activation of guanylyl cyclase --> increases cGMP in smooth muscle --> myosin light chains are dephosphorylated --> myosin can't interact with actin --> vasodilation |