Overview of Pharmacology Basics

Overview of Pharmacology

• Definition: Study of drugs and their effects on biological systems.
• Branches:
  • Pharmacodynamics: Effects of drugs on the body.
  • Pharmacokinetics: Absorption, distribution, metabolism, and excretion of drugs.

Drug Classification

• By Source:
  • Natural (plant, animal, mineral)
  • Synthetic (man-made)
• By Mechanism of Action:
  • Agonists (activate receptors)
  • Antagonists (block receptors)
• By Therapeutic Use:
  • Antibiotics, analgesics, antihypertensives, etc.

Pharmacokinetics

1. Absorption: Process by which a drug enters the bloodstream.
   • Factors: Route of administration, drug formulation, blood flow.
2. Distribution: Dispersion of drugs throughout the body.
   • Influenced by: Blood flow, tissue permeability, protein binding.
3. Metabolism: Biochemical modification of drugs, primarily in the liver.
   • Phase I: Oxidation, reduction, hydrolysis.
   • Phase II: Conjugation.
4. Excretion: Elimination of drugs from the body, mainly through kidneys.

Pharmacodynamics

• Mechanisms of Action:
  • Receptor binding (e.g., enzyme inhibition, ion channel modulation).
• Dose-Response Relationships:
  • Potency: Amount needed for a specific effect.
  • Efficacy: Maximum effect achievable.
• Therapeutic Index: Ratio of toxic dose to therapeutic dose.

Drug Interactions

• Types:
  • Drug-drug interactions
  • Drug-food interactions
  • Synergistic (enhanced effect) vs. antagonistic (reduced effect)
• Consequences: Altered efficacy or increased toxicity.

Adverse Drug Reactions (ADRs)

• Types:
  • Type A (predictable, dose-dependent)
  • Type B (unpredictable, not dose-dependent)
• Monitoring: Regular assessment to identify and manage ADRs.

Clinical Pharmacology

• Personalized Medicine: Tailoring drug therapy based on genetic, environmental, and lifestyle factors.
• Pharmacovigilance: Monitoring drug safety and effectiveness post-marketing.

Important Concepts

• Bioavailability: The proportion of a drug that enters circulation when introduced into the body.
• First-pass Metabolism: The metabolism of a drug before it reaches systemic circulation.
• Half-life: Time taken for the plasma concentration of a drug to reduce by half.

Common Drug Forms

• Solid: Tablets, capsules.
• Liquid: Solutions, suspensions.
• Injectable: Intravenous, intramuscular, subcutaneous.
• Topical: Creams, gels, ointments.

Regulatory Aspects

• Drug Approval Process: Clinical trials (phases I-IV), FDA review, post-marketing surveillance.
• Controlled Substances Act: Classification of drugs based on potential for abuse.

Conclusion

• Pharmacology is essential for understanding drug interactions, effects, and safety in clinical practice.

Overview of Pharmacology

• Pharmacology explores drugs' effects on living systems.
• Key branches include:
  • Pharmacodynamics: Investigates how drugs affect the body.
  • Pharmacokinetics: Looks at drug absorption, distribution, metabolism, and elimination.

Drug Classification

• Drugs can be classified by:
  • Source:
    • Natural (derived from plants, animals, minerals)
    • Synthetic (chemically created)
  • Mechanism of Action:
    • Agonists: Activate receptors.
    • Antagonists: Block receptors.
  • Therapeutic Use: Encompasses various categories like antibiotics, analgesics, antihypertensives.

Pharmacokinetics

• Absorption: How a drug enters circulation; influenced by administration route, formulation, and blood supply.
• Distribution: Dispersion of the drug in the body; affected by blood flow, tissue permeability, and protein binding.
• Metabolism: Mainly occurs in the liver; involves:
  • Phase I: Oxidation, reduction, hydrolysis.
  • Phase II: Conjugation.
• Excretion: Removal of drugs, primarily through the kidneys.

Pharmacodynamics

• Mechanisms include receptor binding, enzyme inhibition, and ion channel modulation.
• Dose-Response Relationships:
  • Potency: Amount required for a specific effect.
  • Efficacy: The highest effect a drug can produce.
  • Therapeutic Index: Comparison of toxic dose to therapeutic dose.

Drug Interactions

• Types include drug-drug and drug-food interactions.
• Can be:
  • Synergistic: Enhanced effect.
  • Antagonistic: Reduced effect.
• Interactions may change drug efficacy or toxicity levels.

Adverse Drug Reactions (ADRs)

• Categories of ADRs:
  • Type A: Predictable and dose-dependent.
  • Type B: Unpredictable and not dependent on dose.
• Regular monitoring is crucial for detecting and managing ADRs.

Clinical Pharmacology

• Focuses on Personalized Medicine, optimizing drug therapy based on individual genetic and lifestyle factors.
• Pharmacovigilance: Ongoing monitoring of drug safety and effectiveness after market release.

Important Concepts

• Bioavailability: Measures how much of a drug reaches systemic circulation.
• First-pass Metabolism: Drug alteration before systemic circulation.
• Half-life: Time required for a drug's plasma concentration to decrease by 50%.

Common Drug Forms

• Solid Forms: Includes tablets and capsules.
• Liquid Forms: Encompasses solutions and suspensions.
• Injectable Forms: Comprises intravenous, intramuscular, and subcutaneous options.
• Topical Forms: Consists of creams, gels, and ointments.

Regulatory Aspects

• Drug Approval Process: Involves clinical trials across four phases, FDA evaluation, and ongoing post-marketing surveillance.
• Controlled Substances Act: Classifies drugs according to their abuse potential.

Conclusion

• Understanding pharmacology is vital for grasping drug interactions, effects, and safety within clinical settings.