Pharmacology: Definitions and Subfields

Pharmacology Basics

• Pharmacology definition: The study of drug interactions within biological systems.
• Pharmacology investigates a drug's journey through and effects on the body.
• Pharmacology covers the origins, production, effects, side effects, poisoning, and treatments of drugs.

Subfields of Pharmacology

• Pharmacokinetics: Studies drug movement inside the body.
• Pharmacodynamics: Explores biochemical and physiological effects and mechanisms of drug actions on the body.
• Pharmacotherapy: Focuses on treating diseases or relieving symptoms using drugs.
• Chemotherapy: Involves the use of drugs to eliminate infecting organisms or cancer cells without harming host cells.
• Clinical Pharmacology: Explores the clinical applications and effects of drugs on human physiology and responses.
• Pharmacogenetics: Studies how genetic variations affect drug treatment outcomes.
• Toxicology: Focuses on the symptoms, mechanisms, treatment, and detection of poisoning caused by chemical substances.

Pharmacokinetics (ADME)

• Pharmacokinetics studies drug movement within the body and how the body alters the drug.
• ADME describes absorption, distribution, metabolism, and excretion processes.
• Absorption, distribution, metabolism, and excretion are related to the onset, duration, and intensity of drug effects.

Pharmacodynamics

• Pharmacodynamics studies the biochemical and physiological effects of drugs.
• Pharmacodynamics studies drug actions and mechanisms within the body.
• Most drugs need to bind to a receptor in order to have an effect.

Clinical pharmacology

• A branch of pharmacology concentrating on drug impact and applications.
• Studies drug effects on human bodies and the body's reaction to medicines.

Pharmacotherapy

• Using medication to treat illnesses or ease symptoms.

Chemotherapy

• This involves the use of particular medications to eradicate cancer cells or infections affecting the system.
• This eliminates the infecting organism or cancer cells, while minimizing any negative effects on the host cells.

Pharmacoepidemiology

• Studies the effects of drugs on populations.

Pharmacoeconomics

• Studies the cost-effectiveness of drug therapy and the overall cost of medications.

Pharmacogenetics

• Understands how genetic variations affects the outcomes of the the drug treatment.
• Some individuals exhibit greater sensitivity to certain drugs due to their genetics.

Toxicology

• Toxicology studies the symptoms, mechanisms, treatment, and detection of poisoning caused by chemical substances.
• "Every drug is a poison; what distinguishes a drug from poison is the dose."
• Drugs can benefit when used correctly; otherwise, drugs cause harm on health, social, and economic level.
• Paracelsus lived from 1493-1541.

Pharmacological Studies

• In vitro studies are conducted outside a living organism in a controlled environment like a test tube or petri dish.
• In vivo studies are conducted within a living organism.
• Pharmacological studies determine the most appropriate drug for diagnosis, treatment, and prevention of diseases.

Drug Definition

• A drug is any mixture with a chemically active compound of biological, plant, or animal origin that can influence biological processes.
• World Health Organization definition of a drug: a substance that modifies physiological systems or pathological conditions for human benefit.

Pharmaceutical Form

• Drugs are combined with inactive excipients and specific ingredients to create pharmaceutical forms.
• These pharmaceutical forms are easier to administer for treatments.

Purpose of Drug Therapy

• Prophylaxis: Prevention of disease.
• Diagnosis: Identifying a disease.
• Treatment: Managing or curing a disease.
• Control: Keeping the disease under control.

Types of Treatment

• Radical Treatment: Administration to completely eliminate the cause of the disease (e.g., infection treatment).
• Symptomatic/Palliative Treatment: Relieves symptoms without addressing the underlying cause (e.g., Using an analgesic for a tooth cavity).
• Prophylactic/Preventive Treatment: Administration to prevent a potential disease.

Key Characteristics of Drug Action

• Selectivity: The drug should affect only the targeted structure, organ, or system while avoiding unwanted effects on other areas.
• Temporary Effect: The drug's effect should cease once the treatment is discontinued; permanent effects indicate poisons.
• Dose-Dependent Effect: The drug's effect is dependent on the administered dose or dose amount given.

Sources of Drugs

• Natural Sources: Plants (leaves, roots, sap, seeds, bark, etc.).
• Natural Sources: Animals (hormones and enzymes).
• Natural Sources: Microorganisms (bacteria and fungi produce antibiotics like penicillin).
• Natural Sources: Minerals (inorganic sources like sodium chloride (NaCl), magnesium salts, etc).
• Synthetically Derived Drugs: Drugs produced through chemical synthesis instead of natural extraction.

Classification of Drugs

• Chemical Structure: Relates to pharmacological effects (e.g., Choline esters, organic phosphates).
• Site of Action: Drugs affecting the digestive, nervous, or endocrine systems.
• Therapeutic Use: Antihypertensives (for high blood pressure), Antipyretics (fever reducers).

Drug Naming System

• Chemical Name: Based on IUPAC nomenclature, describing the drug's chemical structure (e.g., Acetylsalicylic acid).
• Generic Name (Nonproprietary Name): Standard name for healthcare (e.g., Aspirin, Paracetamol).
• Brand Name (Trade Name): Given by the manufacturer with multiple brands for a single drug (e.g., Coraspin, Ataspin, Dispril).

Generic Name Example

• Brand name: Parol
• Generic Name: Paracetamol
• Chemical Name: N-asetil para-amino- fenol 17

Brand Name examples

• Brand Name (coraspin,andol..)
• Generic Name (aspirin, ibuprofen)

Drug Dosages

• Dose: The amount of a drug given at one time.
• Daily Dose: The total amount of drug administered within a 24-hour period.
• Maintenance Dose: Keeps drug's blood levels stable, maintaining its effect.
• Lethal Dose: Amount of drug that causes death.
• Therapeutic Dose: The dose that produces the desired therapeutic effect.

Adverse Drug Effects

• Side Effect: Unintended effects that occur when a drug is used at its normal dosage.
• Toxic Effect: A harmful reaction that can cause discomfort, life-threatening conditions, or even death.
• The benefit/risk ratio should always be carefully considered.

Indications and Contraindications

• Indication: A condition that necessitates a specific treatment or medical intervention.
• Contraindication: A condition that prevents the use of a particular treatment or medical procedure.

Bioavailability

• Bioavailability refers to the portion of the drug that reaches the systemic circulation without undergoing chemical modification.

Drug Formulation

• Drugs are not used in their pure form.
• Drugs mixed with inactive excipients to ensure proper administration.
• These prepared forms are called pharmaceutical forms (e.g., ampoule, tablet, coated tablet, syrup, suppository).
• Drug formulation is mixing the bioactive component with excipients according to specific formulations.

Pharmaceutical Forms

• Solid and Semi-Solid: Tablets (chewable, effervescent, enteric-coated, sublingual, buccal).
• Solid and Semi-Solid: Capsules, Powders, Suppositories (rectal, vaginal).
• Solutions: Oral, injectable, ophthalmic, otic, nasal.
• Solutions: Suspensions (shake before use), Emulsions, Syrups, Elixirs, Topical Forms, Creams.
• Ointments: Pomades, Balms, Gels.
• Patches: Transdermal Patches.
• Forms: Aerosols, Inhalers, Nebulizers.

Types of Tablets

• Tablets contain water and disintegrate in the gastrointestinal tract.
• Chewable Tablet: Are chewed before swallowing and contain medicinal substances without unpleasant taste to consume easily.
• Sublingual Tablet: Placed under the tongue to be absorbed directly into the bloodstream through the oral mucosa.
• Effervescent Tablet: Contain acids releasing carbon dioxide, designed to dissolve or disperse in water before administration.

Tablets - Coated & Buccal

• Enteric-Coated Tablet: Has a coating preventing dissolution in the acidic stomach environment, dissolving instead in the intestines, protecting sensitive drugs or preventing irritation.
• Buccal Tablet: Placed between the cheek and gum to dissolve slowly, allowing gradual drug absorption through the oral mucosa.

Capsule Characteristics

• Capsule: Cylindrical gelatin shells that encase solid or liquid drugs to make swallowing easier.
• These mask unpleasant tastes and odors of medications.
• Capsules are available in various colors and sizes for easy identification.

Pastilles & Powders

• Pastille: Solid, round/oval form with flavored sugar base to dissolve slowly in the localized mouth (e.g., throat soothing).
• Powder: Synthetic or natural drugs ground into a fine powder, and usually taken orally or dissolved in water before use.

Suppositories, Ovules

• Suppository: Cone-shaped for rectal administration made with fatty bases that melt at body temperature. Known as "fitil" in Turkish.
• Ovule (Vaginal Suppository): It resembles a suppository, but is specifically for vaginal use.

Liquid Dosage Forms: Solutions

• Solutions: Prepared by dissolving the active drug ingredient in water or another solvent.
• Applied orally as a gargle.
• Administered as drops for the eyes, nose and ears.
• Solutions can be put into ampoules for parenteral injection

Solutions & Drops

• Solution: A liquid form prepared by dissolving a drug in water or another solvent.

Suspensions

• Suspension: Liquid with solid drug particles not fully dissolved, but dispersed. The suspension settles over time, so shake before use.
• After dilution, store in refrigerator and has shelf life of 15 days.

Injections

• Injections include sterile solutions or suspensions in a water- or oil-based medium.
• Injections are designed for subcutaneous (under skin) or intramuscular (into muscle) administration.
• Injections are available in glass ampoules or airtight rubber-capped vials.

Ampoules for Injection

• Ampoule: Sealed glass container broken before injection, typically contains one single dose of medication.
• Vial (Flacon): Rubber-capped glass container where drug is drawn into a syringe; can be single-dose or multi-dose.

Eye Drops/Ophthalmic Solutions

• Ophthalmic Solutions: Liquid drug formulations specifically designed for eye application.

Ear Drops/Otic Solutions

• Otic Solutions: Liquid drug formulations intended for administration into the ear.

Emulsions & Elixirs

• Emulsion: A liquid dosage form with two immiscible liquid phases, where one liquid is dispersed as small droplets within the other.
• Elixir: Sweetened solution with alcohol and water, used as a vehicle for medicinal substances.

Syrups

• Syrup: Liquid with high sugar concentration to hinder bacteria and fungi.

Enemas

• Enemas: Administered rectally to relieve constipation, and cleanse the intestines before a medical examination.

Ointments

• Ointment: Externally used preparations of active ingredients mixed with bases (such as vaseline and lanolin).

Creams

• Cream: Ointments that contain more water (water-based content).

Gels:

• Gel: Transparent or translucent semi-solid preparations where the drug is dispersed in a gel base.

Transdermal Therapeutic Systems (TTS)

• TTS System: Allows drug absorption through the skin into the bloodstream through a band and provides long-term, controlled release.

Gas Dosage Forms

• Gas Dosage Forms are medicines that are gases (or volatile liquids), administered through a mouthpiece, mask, hood, or endotracheal tube.
• Inhaler delivers powdered/vapor medications to the lungs for respiratory diseases.
• Nebulizer converts liquid medications into a fine vapor delivery to the lungs with inhalation.