Pharmacodynamics NU1107 Student Slides PDF

Introduction to Pharmacology 21 November 1 2024  Aim of the session On completion of this session students should be able to understand the basic pharmacological principles (LO3) 21 November 2 2024  Pharmacodynamic...

Introduction to Pharmacology 21 November 1 2024  Aim of the session On completion of this session students should be able to understand the basic pharmacological principles (LO3) 21 November 2 2024  Pharmacodynamics Pharmacodynamics is the study of the effects and changes drugs cause in the body It focuses on how drugs produce their effects and the relationship between drug concentration and effect Essentially, pharmacodynamics explains ‘what the drug does to the body’ 21 November 3 2024 Drug receptors Definition: Receptors are specific molecules in the body (often proteins) that drugs bind to, leading to a physiological response Types of receptors: Cell Surface Receptors – located on the cell membrane Intracellular receptors – found inside the cell Drug receptor interactions Agonists – drugs that bind to receptors and bind to them to produce a physiological response Antagonists – drugs that bind to receptors but do not bind to them. They block or dampen the effects of agonists Partial Agonists – drugs that bind to and activate receptors but produce a smaller response compared to full agonists Dose response relationship Definition: The relationship between the dose of the drug and the magnitude of its effect Dose responsive curve: a graph plotting a drug dose on the x-axis and the drug effect on the y-axis Threshold dose Efficacy Potency This Photo by Unknown Author is licensed under CC BY-NC-ND Therapeutic Window Definition: The range between the minimum effect dose and the maximum toxic dose of a drug Importance: Ensures that the drug is effective without causing adverse effects Adverse Drug Reactions (ADR’s) Key facts: Unintended, harmful reactions to medicines (known as adverse drug reactions) are among the leading causes of death in many countries. The majority of adverse drug reactions (ADR) are preventable. People in every country are affected by ADRs. In some countries, ADR-related costs such as hospitalization, surgery and lost productivity exceed the cost of medications. No medicine is risk-free. Vigilant assessment of the risks and benefits of medicines promotes patient safety. Examples of ADR’s Oral contraceptives Thromboembolism (blood clots) Statins (for controlling cholesterol) Muscle degeneration Antidepressants – dry mouth ADR’s are categorised into two different types. Type A and Type B. Type A – result from an exaggeration of the drug’s normal pharmacological actions Type B – cannot be predicted from the pharmacology of the drug Application to patient care Understanding pharmacodynamics helps in various aspects of patient care including: Dose regimens – determining the appropriate dose and frequency to achieve therapeutic effects whilst minimizing side effects Drug interactions – recognising how one drug might affect the action of another drug through receptor interactions and other mechanisms Individual variability – considering how genetic factors, age, disease states and other variables can affect drug responses Task Take a minute to look up the following video on ADR’s. Adverse drug reaction awareness week (youtube.com)