Introduction to Pharmacology

Introduction to Pharmacology

• Introduction to pharmacology is a branch of science that investigates the interaction of drugs and biological systems, either in vitro or in vivo.

Basic Concepts

• It provides education on this subject.
• Enables identification of suitable chemical substances for diagnosis, treatment, disease prevention, and other medical purposes.
• Covers various aspects, including the origin, methods of obtaining, effects, side effects, poisoning, and drug metabolism in the body.

Branches of Pharmacology

• Pharmacokinetics: Focuses on what the body does to the drug.
• Absorption, Distribution, Metabolism(biotransformation), Elimination(excretion) and quantitative aspects, especially in time dimensions are essential.
• Pharmacodynamics: Focuses on the basic effects of drugs on physiological events in the human body and their mechanisms.
• Toxicology: The study of poisons or toxic effects of drugs and chemicals (used in everyday life, agriculture, industry).
• Pharmacotherapy: Examines clinical use, indications, contraindications, and interactions of drugs
•  Chemotherapy: Treats diseases caused by bacteria, microorganisms, or parasites.
• Pharmacovigilance: Identifies potential causal relationships between adverse effects and drug use.
• Pharmacogenetics: Examines differences in drug effects between individuals due to genetic differences. 
• Pharmacoeconomics: Analyzes and defines costs of drug treatment to the health system and society.
• Clinical Pharmacology: Focuses on drug studies in humans, aims to identify and develop new drugs.
• Pharmaceutical Technology: Formulating medicines into appropriate pharmaceutical forms (tablets, pills, capsules, elixirs, etc.; injections).

Pharmacokinetnics

• Focuses on how the body affects the drug.
• Includes absorption, distribution, metabolism (biotransformation) and elimination (excretion) of drugs quantitatively in time context.

Pharmacodynamics

• Focuses on the drug's effect on the body.

Basic Concepts Summary

• Dose: The amount of medicine given at one time.
• Drug: Raw material from animals or plants.
• Daily dose: Recommended amount of medicine throughout the day.
• Side effect: Undesirable effects of medicines, even at usual doses.
• Toxic effect: Unpleasant, uncomfortable and even fatal effect on the patient.
• Benefit/risk ratio: Benefits must outweigh harm.
• Safety interval: Distance between therapeutic dose and toxic dose.
• Indication: The effects of the medicine for the intended use.
• Contraindication: Conditions where medicine should not be used.
• Resistance: The development of organisms' resistance to drugs depending on characteristics and ineffectiveness to drugs.
• Tolerance: Progressive decrease in effect with continuous medication use.
• Half-life: Time active substance reduces by half in the body.
• Pharmacopoeia: Book with medicine formulas and recipes.
• Prospectus: Brochure with introductory information about medicine.

Medicine/Drug

• A pure chemical substance for medicine.
• Could be bioactive or a mixture of plant/animal origin with a standardized amount of active substances.

Drug Definition (WHO)

• Substance/product used to modify or investigate physiological systems and pathological conditions.
• Three ways drugs have effect:
  • Effect on body functions/mental functions
  • Replace active substances, salts, or fluids (fluids deficiency)
  • Excrete or destroy harmful substances entering the body.

Key Features of Drug Action

• Selectivity: The drug should act on the related cells and structures.
• Temporary: The effect should disappear when medication is stopped.
• Dose-dependent: Effect varies with dose.

Drug Treatment of Diseases

• Radical Treatment: Completely eliminates disease cause.
• Symptomatic Treatment: Relieves symptoms without removing the cause.
• Prophylactic Treatment: Prevents disease from occurring (examples: vaccines).
• Substitution Treatment: Replaces deficient substances (vitamins, hormones etc.).
• Empiric Treatment: Based on experience, not precise knowledge of cause or nature of disorder.

Sources of Medicines

• Derived from natural sources or prepared synthetically.
• Natural sources: plants, animals, microorganisms, minerals.

DNA Recombination

• A technique for producing medicines, including human interferons, insulins, growth hormones and some vaccines.
• It involves transferring a gene from one organism into another.

Classification of Drugs

• Classified by chemical structures, site of action, clinical conditions, and purposes of use.

Drug Names

• Includes common name, brand name, and chemical name.

New Drug Development

• Stages: Bio/synthesis, screening tests, clinical trials (Phase 1, 2, 3), post marketing trials.
• Structure-Activity Relationship (SAR) is important for finding relationships between chemical structure and biological activity of compounds.

Bioequivalence

• Two pharmaceutical equivalents have similar bioavailability.

Therapeutic Equivalence

• Two pharmaceutical equivalent drugs that have proven bioequivalent.

Therapeutic Examples

• Used by different pharmaceutical properties and mechanisms.

Original and Generic Drugs

• Original Drugs: International term for new medicines proven useful.
• Generic Drugs: Similar to original medication.

Pharmaceutical Forms

•  Solid Forms: tablets, dragees, pills, capsules, cachets, powders, and packets.
•  Liquid Forms: solutions, tinctures, elixirs, syrups, drops, suspensions, emulsions, and enemas.
•  Semi-solid Forms: ointments, pastes, creams.