Pharmacology: An Overview

• Pharmacology comes from "Pharma" (drug) and "Logos"(science).
• It is the study of the interaction of drugs with biological or physiological systems
• It investigates what happens to a drug in the body
• Pharmacology looks at the origins, production, and effects on the body, including side effects, poisoning cases, and their treatments

Subfields of Pharmacology

• Pharmacokinetics
• Pharmacodynamics
• Pharmacotherapy
• Chemotherapy
• Clinical Pharmacology
• Pharmacogenetics
• Toxicology

Pharmacokinetics

• Kinesis refers to movement
• It studies the movement of the drug within the body and how the body modifies the drug
• Pharmacology examines the processes of drug absorption, distribution, metabolism, and excretion
• It looks at their relationship with the onset, duration, and intensity of drug effects
• ADME refers to Absorption, Distribution, Metabolism, and Excretion
• The body's actions on the drug are pharmacokinetics

Pharmacodynamics

• It studies the biochemical and physiological effects of drugs on the body
• It looks at their mechanisms of action
• Most drugs must bind to a receptor to exert an effect
• The drug's actions on the body are pharmacodynamics

Clinical Pharmacology

• This focuses on drugs and their clinical applications
• It studies the effects of drugs on human physiology and the body's responses to these drugs

Pharmacotherapy

• This is concerned with the treatment of diseases or symptom relief using drugs.

Chemotherapy

• This treats systemic infections or cancer using specific drugs
• These drugs eliminate the infecting organism or cancer cells
• They have little to no effect on the host cells

Pharmacoepidemiology

• It is the study of drug effects on a population

Pharmacoeconomics

• This examines the cost-effectiveness of drug therapy and the overall cost of medications

Pharmacogenetics

• It aims to understand how genetic variations influence drug treatment outcomes
• Some patients respond to certain drugs with greater sensitivity than normal

Toxicology

• This is the science of poisons
• It deals with the symptoms, mechanisms, treatment, and detection of poisoning caused by chemical substances
• "Every drug is a poison; what distinguishes a drug from the poison is the dose." - Paracelsus (1493-1541)
• If used correctly and appropriately, a drug can be beneficial; otherwise, it can cause harm
• This harm can impact health, society, and the economy

Pharmacological Studies

• In vitro studies are conducted outside a living organism, e.g., in a test tube or petri dish
• In vivo studies are conducted within a living organism
• Pharmacological studies determine the most suitable drug for diagnosis, treatment, and prophylaxis (prevention) of diseases

Drugs

• A drug is any mixture containing a chemically active compound
• This compound can be of biological, plant, or animal origin
• It is capable of influencing biological processes
• Prophylaxis refers to disease prevention
• According to the World Health Organization (WHO), a drug is a substance that can modify physiological systems or pathological conditions for human benefit

Pharmaceutical Forms

• Substances are not used in their pure form
• They are combined with specific excipients (inactive ingredients)
• This creates pharmaceutical forms, making them easier to administer to humans
• Pharmaceutical form refers to the presentation form of a drug

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: Drug administration to completely eliminate the cause of the disease, e.g., infection treatment
• Symptomatic/Palliative Treatment: Drugs used to relieve symptoms without addressing the underlying cause of the disease, e.g., analgesic to relieve pain
• Prophylactic/Preventive Treatment: Drug 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 and permanent effects are characteristic of poisons
• Dose-Dependent Effect: The drug's effect depends on the administered dose, and the dose refers to the amount of drug given at one time

Sources of Drugs

• Natural sources include plants, animals, microorganisms, and minerals
• Plants: Leaves, roots, sap, seeds, bark, etc.
• Animals: Hormones and enzymes
• Microorganisms: Bacteria and fungi, e.g., Penicillin
• Minerals (Inorganic Sources): Sodium chloride (NaCl), Magnesium salts, etc.
• Synthetically Derived Drugs: Drugs produced through chemical synthesis rather than being extracted from natural sources

Classification of Drugs

• Based on Chemical Structure: Related to pharmacological effects, e.g., Choline esters, Organic phosphates
• Based on Site of Action: Drugs affecting the digestive and nervous systems, endocrine system drugs
• Based on Therapeutic Use: Antihypertensives (for high blood pressure), Antipyretics (fever reducers)

Drug Naming System

• Chemical Name: Assigned based on the International Union of Pure and Applied Chemistry (IUPAC) nomenclature, which describes the chemical structure of the drug, e.g., Acetylsalicylic acid, N-(4-hydroxyphenyl)acetamide (Acetaminophen)
• Generic Name (Nonproprietary Name): The standard name used in medicine, pharmacy, and healthcare fields, as well as in education, scientific meetings, and international communication, e.g., Aspirin, Paracetamol, Diclofenac
• Brand Name (Trade Name): The name given by the manufacturer, meaning that a single drug may have multiple brand names, e.g., Coraspin, Ataspin, Dispril

Drug Dose

• 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: The dose required to keep the drug's blood levels stable and maintain its therapeutic effect
• Lethal Dose: The amount of a 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
• Even at regular doses, drugs can sometimes cause toxic effects
• the benefit/risk ratio should always be carefully considered

Indications and Contraindications

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

Bioavailability

• It refers to the portion of a drug that reaches the systemic circulation without undergoing chemical modification

Drug Formulation

• Drugs are generally not used in their pure form
• They are prepared by mixing the active drug with inactive excipients to ensure proper administration
• These prepared forms are called pharmaceutical forms (e.g., ampoule, tablet, coated tablet, syrup, suppository)
• The process of mixing the bioactive component with excipients according to specific formulations is known as drug formulation

Solid and Semi-Solid Pharmaceutical Forms

• Tablets (chewable, effervescent, enteric-coated, sublingual, buccal)
• Capsules
• Powders
• Suppositories (rectal, vaginal)

Liquid Pharmaceutical Forms

• Solutions (oral, injectable, ophthalmic, otic, nasal)
• Suspensions
• Emulsions
• Syrups
• Elixirs
• Topical Forms
• Creams

Other

• Ointments (Pomades, Balms)
• Gels
• Transdermal Patches

Gaseous Forms

• Aerosols
• Inhalers
• Nebulizers

Tablets

• Water is absorbed in tablets, and this makes it swell and disintegrate
• Chewable: It is designed to be chewed before swallowing and contains medicinal substances that don't leave a bitter or unpleasant taste for easier consumption
• Sublingual: Placed under the tongue, the drug is absorbed directly into the bloodstream through the oral mucosa
• Effervescent It is a solid dosage form containing acids that release carbon dioxide when dissolved in water and dissolve or disperse in water before administration
• Enteric-Coated Tablet: Has a special coating that prevents it from dissolving in the acidic environment of the stomach(HCl)
• It is designed to dissolve in the intestines, protecting sensitive drugs from stomach acid or preventing irritation of the gastric mucosa
• Buccal : Placed between the cheek and gum, where it dissolves slowly and allows for gradual absorption of the drug through the oral mucosa

Capsules

• These are cylindrical gelatin shells that encase solid or liquid drugs, making them easier to swallow
• They mask unpleasant tastes and odors of medications
• Available in various colors and sizes for easy identification

Pastille

• It is a solid, round, or oval dosage form made with a flavored sugar base
• It will dissolve slowly in the mouth, providing a localized effect such as throat soothing

Powder

• Synthetic or natural drugs that have been ground into a fine powder
• Usually taken orally or dissolved in water before use

Suppository

• It is a cone-shaped pharmaceutical form designed for rectal administration
• Made with fatty bases that remain solid at temperature but melt at body temperature
• Commonly known as a "fitil" in Turkish
• Ovule (Vaginal Suppository): It is a suppository-like dosage form specifically designed for vaginal administration in women

Liquids

• Solutions: These have been prepared by dissolving the active drug ingredient in water or another solvent.
• It is called a gargle when applied orally
• The solution can be administered as drops for the eyes, nose, or ears and even placed in ampoules for parenteral use

Solution Small volumes called drops

• Uses :A liquid dosage form made from dissolving the drug in water or another solvent
• They are for the eyes, ears, or nose.
• Suspensions are solid + liquids liquid dosage forms where solid drug particles don't fully dissolve, but remain dispersed in a liquid

Injections

• Solutions Injections are solutions or suspensions with a stable base (either water or oil) to be ready for administration under the skin or directly into the muscle.
• They use ampoules or sealed viles

Ampoules

• A sealed glass container. It is a single use glass container which must be broken to access the drugs,

Viles

• Viles are rubber capped container which the drugs are drawn from, this means that it has to be drawn with a syringe and can be used for both single and multi-dose injections.

Eye Drops / Ophthalmic Solutions: Liquid drug formulations specifically designed for eye application.

Ear Drops / Otic Solutions: Liquid drug formulations intended for administration into the ear Emulsion

A liquid dosage form consisting of two immiscible liquid phases, where one liquid is dispersed as small droplets within the other Elixir

A sweetened solution containing alcohol and water, used as a vehicle for medicinal substances. Syrup

• Syrups, has very high concentrations of high sugar concetrations
• These high concentrates prevent the creation of bacteria in the drugs

Enema

• Enema
• They have Lavman properties
• solutions are applied rectally with the purpose of constipation relief and cleansing the intestines for tests

Ointment

• Externally used that are mixed preparations with the help of a base and active ingredients: vaseline and lanolin

Creams

• Contain more water then the ointments and have a water base

Gels

• Transparent preepertaripns in which the drugs are disbursed in in semi-solid that are transcluscent

TTS

• A type of system which releases drugs through skin absorption in the blood stream.
• Often the form of a band a Regularly medication

Gas Dosage Forms

• Gas Dosage Forms: Medicines that are gases or volatile liquids can be administered administered by inhalation using a mouthpiece or other mouth applications

Inhaler: Delivers medications directly to the lungs in fine powder or vapor forms. They are mostly used for drugs for repistoty problems