Pharmacology Overview

Definition

• Study of medications or chemical compounds interacting with living systems.
• Aim: Produce specific effects on molecules, cells, tissues, and whole organisms.

Drug Development Process

• Developing new medications is time-consuming and costly.
• Three Steps of Development:
  1. Discovery: Identify a candidate compound as a potential therapeutic agent.
  2. Pre-clinical Research: Test compound on cell cultures and animals for safety.
  3. Clinical Development: Conduct clinical trials on humans to ensure safety and efficacy.

Clinical Trials Phases

• Phase 1: Test safety in a small group of healthy volunteers.
• Phase 2: Assess effectiveness and dosages in a moderately sized group of affected individuals.
• Phase 3: Compare new medication to existing treatments in a large group, replicating real-life settings.
• Phase 4 (Post-Market Surveillance): Monitor for long-term or rare side effects.

Medication Names

• Chemical Name: Describes chemical structure (e.g., N-acetyl-p-aminophenol).
• Generic Name: Shortened chemical name used by healthcare professionals (e.g., Paracetamol/Acetaminophen).
• Brand Name: Given by pharmaceutical companies (e.g., Panadol, Tylenol).

Pharmacokinetics

• Describes movement and modification of medication in the body (ADME):
  • Absorption: Entry into circulation.
  • Distribution: Spread to tissues.
  • Metabolism: Breakdown within the body.
  • Excretion: Elimination through urine or feces.

Pharmacodynamics

• Focuses on the effects of medication on the body.
• Involves receptor binding and signal cascades affecting cell function.
• Therapeutic Effect: Desired beneficial outcome.
• Side Effects: Unwanted outcomes (e.g., nausea, fatigue).

Therapeutic Index

• Ratio of toxic dose to effective dose (TD50/ED50).
• Wide Index: Safer medication.
• Narrow Index: Requires careful monitoring (e.g., Warfarin, Lithium).

Drug Interactions

• Pharmacokinetic Interactions: Alter absorption, metabolism, or excretion.
• Pharmacodynamic Interactions: Medications enhance or counteract each other's effects.
• Synergistic Effect: Enhanced combined effect.
• Antagonistic Effect: Opposing effects reduce overall impact.

Key Takeaways

• Medications developed through discovery, preclinical, and clinical phases.
• Three names: chemical, generic, brand.
• Pharmacokinetics: body’s effect on medication.
• Pharmacodynamics: medication's effect on body.
• Narrow therapeutic index drugs need monitoring.
• Drug interactions occur on pharmacokinetic and pharmacodynamic levels.