Overview of Pharmacology

Overview of Pharmacology

• Definition: Study of drugs and their interactions with living organisms.
• Branches:
  • Pharmacodynamics: Effects of drugs on the body.
  • Pharmacokinetics: Absorption, distribution, metabolism, and excretion of drugs.

Drug Classification

• Based on effects:
  • Therapeutic: Treat specific diseases.
  • Non-therapeutic: Used for recreational or other purposes.
• By source:
  • Natural: Derived from plants, animals.
  • Synthetic: Chemically created in laboratories.
• By mechanism of action:
  • Agonists: Activate receptors.
  • Antagonists: Block receptors.

Key Pharmacokinetic Processes

1. Absorption

   • Route of administration affects absorption rate (oral, intravenous, etc.)
   • Bioavailability: Fraction of administered drug that reaches systemic circulation.

2. Distribution

   • Volume of distribution (Vd): Measure of drug dispersion in body tissues.
   • Factors: Plasma protein binding, blood flow, tissue permeability.

3. Metabolism

   • Liver is primary site for drug metabolism.
   • Phase I reactions: Modification of drug (oxidation, reduction).
   • Phase II reactions: Conjugation to increase solubility (glucuronidation, sulfation).

4. Excretion

   • Primary route is renal (kidneys).
   • Can also occur via bile, sweat, saliva, lungs.

Pharmacodynamics Principles

• Mechanism of Action: How drugs produce their effects (e.g., receptor binding).
• Dose-Response Relationship:
  • Potency: Amount of drug needed to produce effect.
  • Efficacy: Maximum effect achievable with a drug.
• Therapeutic Index: Ratio of toxic dose to therapeutic dose; indicates safety.

Adverse Drug Reactions

• Types:
  • Type A: Predictable, dose-dependent (e.g., side effects).
  • Type B: Unpredictable, not dose-dependent (e.g., allergic reactions).
• Monitoring and management are crucial to patient safety.

Drug Interactions

• Pharmacodynamic interactions: Combined effects of drugs (synergistic or antagonistic).
• Pharmacokinetic interactions: One drug affects the absorption, distribution, metabolism, or excretion of another.

Special Considerations

• Age: Pediatric and geriatric populations may metabolize drugs differently.
• Genetics: Pharmacogenomics influences drug response and metabolism.
• Pregnancy: Drug effects can vary; some are contraindicated.

Clinical Applications

• Drug Development: Preclinical and clinical trial phases.
• Prescription Practices: Importance of patient history, potential interactions, and monitoring.
• Evidence-Based Medicine: Use of clinical evidence to guide drug therapy decisions.

Overview of Pharmacology

• Pharmacology examines the effects of drugs on living organisms and their biological interactions.
• Two main branches:
  • Pharmacodynamics studies how drugs affect the body.
  • Pharmacokinetics explores drug absorption, distribution, metabolism, and excretion.

Drug Classification

• Divided by effects:
  • Therapeutic drugs target specific diseases for treatment.
  • Non-therapeutic drugs serve recreational or alternative purposes.
• Classifications by source:
  • Natural drugs originate from plants or animals.
  • Synthetic drugs are chemically engineered in labs.
• Grouped by mechanism of action:
  • Agonists activate receptors in the body.
  • Antagonists inhibit receptor activity.

Key Pharmacokinetic Processes

• Absorption is influenced by the route of administration (e.g., oral, intravenous).
  • Bioavailability refers to the proportion of a drug that enters systemic circulation.
• Distribution measures how a drug disperses through body tissues, quantified as volume of distribution (Vd).
  • Influencing factors include plasma protein binding, blood flow, and tissue permeability.
• Metabolism primarily occurs in the liver.
  • Phase I reactions involve drug modification through oxidation or reduction.
  • Phase II reactions enhance solubility via conjugation (e.g., glucuronidation, sulfation).
• Excretion is mostly renal via the kidneys, but can also occur through bile, sweat, saliva, and lungs.

Pharmacodynamics Principles

• Mechanism of Action details how drugs produce effects through processes like receptor binding.
• Dose-Response Relationship includes:
  • Potency, indicating the amount required for an effect.
  • Efficacy, the maximum achievable effect of a drug.
• Therapeutic Index is the safety measure, calculated as the ratio of toxic dose to therapeutic dose.

Adverse Drug Reactions

• Types of reactions include:
  • Type A: Predictable and dose-dependent side effects.
  • Type B: Unpredictable reactions that are not dose-dependent, such as allergies.
• Monitoring and managing reactions is essential for patient safety.

Drug Interactions

• Pharmacodynamic interactions describe how drugs influence each other's effects (synergistic or antagonistic).
• Pharmacokinetic interactions occur when one drug alters the absorption, distribution, metabolism, or excretion of another.

Special Considerations

• Age impacts drug metabolism, especially in pediatric and geriatric populations.
• Genetics and pharmacogenomics affect individual drug responses and metabolism.
• Pregnancy alters drug effects; certain drugs may be contraindicated during this period.

Clinical Applications

• Drug Development consists of preclinical studies and clinical trials.
• Prescription Practices emphasize understanding patient history, potential drug interactions, and continuous monitoring.
• Evidence-Based Medicine utilizes clinical research and data to inform drug therapy decisions.

This quiz covers the fundamental concepts of pharmacology, including drug classification, key pharmacokinetic processes, and their effects on living organisms. Students will explore the branches of pharmacodynamics and pharmacokinetics as well as various drug sources and mechanisms of action.