Basic Concepts of Pharmacology

Basic Concepts of Pharmacology

• Definition: Study of drugs, their properties, effects, and how they interact with biological systems.

• Pharmacokinetics: How the body affects a drug (absorption, distribution, metabolism, excretion - ADME).

  • Absorption: Process of a drug entering the bloodstream.
  • Distribution: Movement of the drug throughout the body.
  • Metabolism: Biochemical modification of the drug, primarily in the liver.
  • Excretion: Elimination of the drug from the body, primarily via the kidneys.

• Pharmacodynamics: How a drug affects the body.

  • Mechanism of Action: How a drug produces its effects (e.g., receptor binding, enzyme inhibition).
  • Dose-Response Relationship: Relationship between the dose of a drug and the magnitude of its effect.

Drug Classification

• By Source:

  • Natural: Derived from plants, animals, minerals.
  • Synthetic: Chemically manufactured.

• By Action:

  • Agonists: Activate receptors to produce a biological response.
  • Antagonists: Block receptors to inhibit a biological response.

• By Therapeutic Use:

  • Analgesics: Pain relief (e.g., acetaminophen, ibuprofen).
  • Antibiotics: Fight infections (e.g., penicillin, amoxicillin).
  • Antihypertensives: Lower blood pressure (e.g., lisinopril, amlodipine).

Drug Administration Routes

• Oral: Taken by mouth, absorbed through the gastrointestinal tract.
• Intravenous (IV): Directly into the bloodstream; rapid effect.
• Intramuscular (IM): Injected into muscle tissue; moderate absorption.
• Subcutaneous (SC): Injected under the skin; slower absorption.
• Topical: Applied to skin or mucous membranes for local effect.

Drug Interactions

• Synergistic: Combined effect greater than individual effects.
• Antagonistic: One drug reduces the effect of another.
• Additive: Combined effect equals the sum of individual effects.

Adverse Drug Reactions (ADRs)

• Definition: Undesired or harmful responses to a drug.
• Types:
  • Allergic Reactions: Immune response to a drug (e.g., rashes, anaphylaxis).
  • Toxic Reactions: Harmful effects due to excessive dosing or sensitivity.
  • Side Effects: Secondary effects that are not the main therapeutic purpose.

Pharmacology in Practice

• Prescribing: The process of determining the appropriate medication for a patient.
• Monitoring: Assessing the effects and side effects of medications during treatment.
• Patient Education: Informing patients about their medications, proper usage, and potential side effects.

Key Terms

• Bioavailability: The proportion of a drug that enters circulation when introduced to the body.
• Half-life: Time taken for the blood concentration of a drug to be reduced by half.
• Therapeutic Index: Measure of the safety of a drug, comparing the dose that produces a therapeutic effect to the dose that produces toxicity.

Basic Concepts of Pharmacology

• Study of drugs encompasses their properties, effects, and interactions with biological systems.
• Pharmacokinetics involves the processes of Absorption, Distribution, Metabolism, and Excretion (ADME).
• Absorption refers to how a drug enters the bloodstream from its site of administration.
• Distribution relates to the movement of a drug throughout bodily tissues and fluids.
• Metabolism primarily occurs in the liver, modifying the chemical structure of drugs.
• Excretion is the elimination of drugs from the body, mainly via the kidneys.
• Pharmacodynamics studies the effects of drugs on the body and their mechanisms of action.
• Mechanisms of action can include receptor binding and enzyme inhibition.
• The Dose-Response Relationship illustrates the connection between drug dosage and its effect magnitude.

Drug Classification

• Drugs can be classified by their source:
  • Natural drugs come from plants, animals, or minerals.
  • Synthetic drugs are chemically manufactured.
• By action, drugs are categorized into:
  • Agonists that activate receptors to produce a biological response.
  • Antagonists that block receptors and inhibit biological responses.
• Therapeutically, drugs include:
  • Analgesics for pain relief, e.g., acetaminophen and ibuprofen.
  • Antibiotics that combat infections, e.g., penicillin and amoxicillin.
  • Antihypertensives that lower blood pressure, e.g., lisinopril and amlodipine.

Drug Administration Routes

• Oral administration involves taking drugs by mouth, absorbed in the gastrointestinal tract.
• Intravenous (IV) administration provides rapid effects by delivering drugs directly into the bloodstream.
• Intramuscular (IM) injections are given into muscle tissue, resulting in moderate absorption rates.
• Subcutaneous (SC) injections are placed under the skin, leading to slower absorption.
• Topical applications target skin or mucous membranes for localized effects.

Drug Interactions

• Synergistic effects enhance the overall impact of combined drugs beyond their individual effects.
• Antagonistic interactions result when one drug diminishes the effects of another.
• Additive interactions occur when the total effect equals the sum of the effects of the individual drugs involved.

Adverse Drug Reactions (ADRs)

• ADRs are harmful, unintended responses occurring as a result of drug treatment.
• Types of ADRs include:
  • Allergic reactions, which are immune responses manifesting as rashes or anaphylaxis.
  • Toxic reactions arising from excessive dosing or individual sensitivity to the drug.
  • Side effects that are secondary and not the primary aim of the therapy.

Pharmacology in Practice

• Prescribing involves identifying the appropriate medication based on a patient’s needs.
• Monitoring includes evaluating the therapeutic and adverse effects of medications throughout treatment.
• Patient education is critical in informing individuals about their medications, including usage instructions and potential side effects.

Key Terms

• Bioavailability measures the fraction of an administered drug that reaches systemic circulation.
• Half-life is the duration required for the plasma concentration of the drug to decrease by 50%.
• Therapeutic index indicates drug safety, comparing the dosage that leads to therapeutic benefits against the dosage causing toxicity.

This quiz covers essential concepts in pharmacology, including pharmacokinetics and pharmacodynamics. Explore the processes of drug absorption, distribution, metabolism, and excretion, as well as drug classification based on source and action. Test your knowledge on how drugs interact with biological systems.