Topic 1 & 2: Basic Veterinary Pharmacology Introduction + Drug Sources, Names, Classification and Dosage Forms

Initial vocabulary and concepts from Topic 1 and 2 of Basic Veterinary Pharmacology, including terminology, history, drug sources, and dosage forms.

Veterinary Pharmacology

The study of how drugs interact with animals and how these drugs are used to prevent, diagnose, treat, or control disease.

Pharmacology

The study of substances that interact with living systems through chemical processes.

Drug

Any substance that can bring about a change in biological function through chemical action.

Medicine

A drug used for diagnosis, prevention, treatment, or control of disease.

Therapeutics

The use of drugs to treat disease.

Toxicology

The study of harmful or undesirable effects of chemicals or drugs.

Pharmacy

The preparation, dispensing, and proper handling of medicines.

Pharmacokinetics

The study of what the body does to the drug, focusing on absorption, distribution, metabolism, and excretion.

Pharmacodynamics

The study of what the drug does to the body, focusing on receptors, mechanisms of action, and therapeutic and toxic effects.

AADME: Administration, Absorption, Distribution, Metabolism, Excretion

The key physiological processes that govern the time course of drug fate in the body (pharmacokinetics)

Mineral Source

Drugs obtained from inorganic sources such as sulfur, iron, electrolytes, magnesium sulfate, and iodine.

Botanical Source

Drugs obtained from plants or plant-derived chemicals, including digitalis, opioids, atropine, and morphine.

Animal Source

Drugs obtained from animal tissues or secretions, such as insulin, thyroid hormone, lanolin, and heparin.

Synthetic Source

Completely man-made chemical drugs such as aspirin, steroids, procaine, sulfonamides, and many anesthetics.

Biological Source

Drugs produced by microorganisms or biological systems, such as antibiotics (penicillins, tetracyclines) and ergot.

• multiple species

• breed differences

• food-producing animals

• herd/flock medicine

• different dosage forms

• owner compliance

• public health

unique challenges that make veterinary pharmacology unique (

Comparative Pharmacology

A central theme in veterinary pharmacology asking how a drug behaves across different species, regarding dosage adjustments, metabolism, and residues.

• what is the diagnosis?

• what is the target?

• which animal species is involved?

• what is the safest effective drug?

• What route is appropriate?

• what adverse effects are possible?

• Is the animal used for food?

• are there legal restrictions?

things to consider when making a rational drug decision

Therapeutic Effect

A desired beneficial effect, such as an antibiotic killing susceptible bacteria.

Adverse Effect

An undesired effect occurring at a normal dose, such as vomiting after medication.

Toxic Effect

A harmful effect that is often dose-related, such as kidney damage from an excessive dose.

Side Effect

A secondary effect that may or may not be harmful, such as sedation from an antihistamine.

Contraindication

A specific situation where a drug should not be used, such as avoiding certain NSAIDs in severe renal disease.

Ebers Papyrus

An ancient Egyptian medical text from c. $1550$ BCE containing remedies and formulas; one of the earliest examples of organized drug knowledge.

Dioscorides — De Materia Medica

A classical reference from c. $50$–$70$ CE describing medicinal plants, minerals, and animal products influential for centuries.

Paracelsus

A figure who lived between $1493$–$1541$ who promoted specific drug use and emphasized that dose determines whether a substance is a remedy or poison.

Valerius Cordus — Dispensatorium

Publisher of the first printed pharmacopoeia in $1547$, standardizing medicinal preparations and dosages.

Sir Christopher Wren

Performed one of the earliest recorded intravenous injections in $1656$ using opium in a dog.

William Withering

Reported the use of foxglove extracts for "dropsy" in $1783$, which was later linked to digitalis effects on the heart.

Friedrich Sertürner

Isolated morphine from opium in $1805$, a milestone in isolating active principles from crude plants.

Mathieu Orfila

Published Toxicologie Générale in $1813$ and helped establish toxicology as a scientific discipline.

Rudolf Buchheim

Published a pharmacology text in $1849$ and established one of the first true experimental pharmacology laboratories.

Oswald Schmiedeberg

A Professor of Pharmacology at Strasbourg who published an influential textbook in $1883$ and helped establish it as an independent experimental science.

John Jacob Abel

Known as the father of American pharmacology; helped found the American Society for Pharmacology and Experimental Therapeutics in $1908$.

Paul Ehrlich

Developed the "magic bullet" concept and introduced Salvarsan for syphilis in $1909$–$10$, an early example of antimicrobial chemotherapy.

Alexander Fleming

Discovered penicillin in $1928$ after observing that mold inhibited bacterial growth.

Abelardo Aguilar

Filipino scientist who sent soil samples from Iloilo to Eli Lilly, leading to the isolation of erythromycin (marketed as Ilosone).

• mineral

• plany/botanical

• animal

• microbial/biological

• synthetic

• semi-synthetic

• biotechnology-derived

different sources of drugs (7)

Active Pharmaceutical Ingredient (API)

The actual drug substance responsible for the therapeutic effect.

Excipient

An inactive ingredient added to help formulation, stability, taste, appearance, or delivery.

Vehicle

A carrier or medium in which the drug is dissolved or suspended.

Dosage Form

The physical form of the drug product, such as tablet, capsule, solution, suspension, or ointment.

strength

amount of drug in one solid unit, eg. 50mg/tablet

concentration

amount of drug per liquid volume, e.g. 100mg/mL

Chemical Name

A name describing the chemical structure of the drug; usually long and complex

ex.: N-(2,6-dimethylphenyl)-5,6-

dihydro-4H-1,3-thiazin-2-amine

Generic Name

The official active ingredient name that is not owned by one company; preferred in medical records and prescriptions, (e.g. xylazine)

Brand Name

A company-owned product name, also known as a proprietary or trade name. (e.g.: Rompun®)

code name

temporary research name during development; may be used before official naming

generic name

which drug name is preferred in medical records?

Generics Act of 1988 (Republic Act No. 6675)

• A law stating that physicians, dentists, and veterinarians must write prescriptions using the generic name; brand name may be included but not required

• manufacturers and importers must prominently feature the generic name on drug packaging, labels, and promotional material

• different brands contain the same generic drug

• generic/brand name is confused with another generic/brand name

• same drug comes in different strengths

• owner uses a human medicine name

• drug order doesn’t include strength or concentration

why drug names matter in veterinary practice

by:

• therapeutic use

• body system affected

• mechanism of action

• chemical class

• source

• legal status

• route or dosage form

major ways to classify drugs

Semi-synthetic Drug

A natural drug that is chemically modified to improve properties, such as ampicillin or amoxicillin.

Tablet

A compressed powder containing drug and excipients that may be scored, coated, or chewable.

capsule

drug powder or liquid inside a shell (gelatin or hydroxypropyl methylcellulose) and shell dissolves after administration

Bolus

A large tablet often used for administration in cattle and other large animals.

powder

dry, finely divided drug preparation; can be mixed with feed or water

granules

powder particles that have been aggregated to form a larger mass, usually 2-4mm in diameter

Solution

A homogeneous (single-phase) mixture where the drug is dissolved completely in a solvent.

Suspension

A heterogeneous system in which finely divided solid particles are dispersed in a liquid and must be shaken before use.

emulsion

mixture of oil and water phases; may separate which is why it needs to be shaken as directed

syrup

drug in sugar-containing liquid; improves palatability

elixir

sweetened alcohol-containing liquid, usually for internal use

Tincture

A preparation created by extracting active ingredients using an alcohol-based solvent, usually $15$–$80\%$ ethanol.

injectable

created by extracting active ingredients from plants or chemicals using an alcohol-based solvent (usually 15-80% ethanol)

ointment

greasy, semisolid preparation; for skin, eye, ear, wound applications

cream

semusolid emulsion, usually less greasy; skin conditions

gel

transparent, non-greasy, semisolid consisting of three-dimensional polymeric matrix that traps or entangles a liquid; for skin, oral, periodontal or topical use

Paste

A thick semisolid with high solid content, commonly used for oral equine dewormers.

note: Not every dosage form can be used by every route. An injectable suspension may be appropriate for IM or SQ use but may not be safe IV unless specifically labeled for IV use.