Mini Episode: Fundamentals: Testings Tests, Addictions vs Dependence, How Do We Alter Drug Absorption, What Do Drugs Do?

The Poison Lab

Concepts in this episode

1. testing our tests
   • Sensitivity: Rate of Positive test in those who have the disease
   • Specificity: Rate of negative test in those without the disease
   • Positive predictive value: True positive/ True Positive + False Positive
   • Negative predictive value: True negative/True negative + False negative

• (PK) Bioavailablity = Amount of drug available to be used by the body
  • Oral Bioavailablity= Dose- Fraction excreted unchanged- Fraction metabolized in gut- Fraction metabolized by liver
• How drugs interact with the body (PD)
  • Agonist- stimulates receptor
  • Partial agonist- Activation of receptor with ceiling effect, never achieves maximal activation
  • Antagonist- Prevents receptor activation
  • Inverse agonist- induces an opposite effect as an agonist after binding receptor
• Addiction vs dependance
  • Addiction- Relationship between user and substance
    • A few definitions but frequently involving consequences in life from use and loss of control over use of substance
  • Dependence- Physiologic changes in body due to chronic use
    • Down regulation of stimulated receptors
    • Physiologic basis for tolerance and withdrawal