Lecture 21 - PD Flashcards
(22 cards)
What is pharmacodynamics?
Study of the biochemical and physiological effects of drugs and their mechanisms of action.
What does ED50 measure?
Dose for 50% effective response.
What does TD50 measure?
Dose for 50% toxic response.
What does LD50 measure?
Lethal dose for 50%.
Describe the typical shape of a dose-response curve.
Typically sigmoid-shaped.
What does a larger therapeutic index (TI) indicate?
A safer drug with a greater margin between effective and toxic dose.
What is the formula for calculating the Therapeutic Index (TI)?
TI = TD50 / ED50
What are drugs?
Purified active compounds with well-defined pharmacokinetics and pharmacodynamics; regulated.
What are nutraceuticals?
Products derived from food sources with extra health benefits; less regulated.
What are natural products?
Plant, mineral, or animal-based preparations often containing multiple components.
What challenges exist in testing for adverse effects of natural products?
Identification of active/toxic components can be difficult, products often contain mixtures, variability in composition, limited data on safety.
List common adverse effects reported for natural products.
- Skin reactions (rash, itching)
- Gastrointestinal (nausea, vomiting, abdominal pain)
- CNS symptoms (dizziness, headache, fatigue)
What are the main sources of safety data for natural products?
- Case reports
- Preclinical in vitro assays during product development.
What are drug interactions?
Occur when the effect of one drug is altered by the presence of another substance.
What types of drug interactions exist?
- Synergistic: Combined effect greater than additive.
- Antagonistic: Combined effect less than additive.
Give an example of a drug interaction involving natural products.
Green Tea and Raloxifene: Unexpected decrease in drug levels despite CYP inhibition.
What clinical importance do drug interactions have?
Interactions are frequent, especially in patients on multiple drugs; may require dose adjustments or alternative medications.
What is a resource for checking drug interactions?
Drug Interaction Databases (e.g., DIDB) or New Zealand Formulary interactions checker.
True or False: Adverse effects of natural products are always well-documented.
False.
Fill in the blank: The relationship between drug concentration and effect is a key concept in _______.
pharmacodynamics
What can cause a left-shifted adverse effects curve?
Lower dose causes toxicity, indicating the drug is less safe.
