L1 - Introduction to pharmacology

What is Pharmacology?

The science of drugs, including their mechanisms of action, measurement of effects, discovery, design, development, and actions on and by the organism

. What is Toxicology?

The branch of pharmacology that focuses on the harmful effects of chemicals, including drugs

. What is Therapeutics?

The medicinal use of drugs to treat or relieve the symptoms of disease

. Are all drugs considered medicines?

No, not all drugs are medicines

. What is Pharmacy?

How drugs are formulated and dispensed for use as medicines, including the law governing their medicinal use

. What is the definition of a drug?

A chemical substance of known structure, other than a nutrient or essential dietary ingredient, which produces a biological effect when administered to a living organism

. What three types of names do therapeutic drugs typically have?

Chemical name, common name, and proprietary or trade names

. What is an example of a chemical drug name?

(RS)-2-(4-(2-methylpropyl)phenyl)propanoic acid is the chemical name for ibuprofen

. How can drugs be categorized by therapeutic use?

Grouping drugs according to clinical use, such as analgesics, antihypertensives, or antibiotics

. How can drugs be categorized by mechanism of action?

Grouping drugs based on how they act biologically, such as cyclooxygenase inhibitors or beta-blockers

. What is the mechanism of action and therapeutic use of Ibuprofen?

Ibuprofen is a cyclooxygenase inhibitor (mechanism of action) that acts as an analgesic (therapeutic use)

. What are examples of trade or proprietary names for Ibuprofen?

Nurofen and Advil

. What is the fundamental mechanism by which drugs produce effects?

Drugs are exogenous molecules that mimic or block the actions of endogenous molecules

. What was Paul Ehrlich's key statement on drug binding?

"A drug will not work unless it is bound"

. What are the four main types of target proteins for drugs?

Receptors for neurotransmitters or hormones, enzymes, ion channels, and carrier or transporter molecules

. What is a ligand?

A small drug molecule that binds to a large target protein

. What are steric factors in drug binding?

The size and flexibility of a drug molecule that determine how well it fits into its binding site

. Which chemical bonds usually mediate reversible drug binding?

Hydrophobic interactions, hydrogen bonds, and weaker van der Waals interactions

. Which chemical bonds mediate irreversible drug binding?

Covalent interactions

. What is the outcome of forming a ligand-protein complex?

It alters the biological activity of the target protein

. What is drug specificity?

The ability of a drug to bind in a highly precise way to a specific protein target

. What is drug selectivity?

The ability of a drug to produce a specific therapeutic effect without causing side effects in other organ systems

. Why can a specific drug still be non-selective?

If its single molecular target is present in multiple organ systems (e.g., both cardiovascular and gastrointestinal systems)

. What is Pharmacodynamics (PD)?

What the drug does to the body, detailing the physiological consequences of the drug's actions at a molecular level

. What is Pharmacokinetics (PK)?

What the body does to the drug, describing how the drug is absorbed, distributed, metabolised, and excreted by the organism

. What is the purpose of PK/PD studies?

To combine pharmacodynamics and pharmacokinetics to gain a true understanding of a drug's therapeutic effectiveness

. What does the acronym ADME stand for?

Absorption, Distribution, Metabolism, and Excretion

. What is drug absorption?

How much and how quickly a drug enters the blood plasma

. Which chemical properties influence drug absorption?

Molecular size, lipid solubility (influenced by ionization), and chemical stability (such as acid stability in the stomach)

. How does pH change along the gastrointestinal tract?

Stomach pH ranges from 1.4–2.1 (fasting) to 3–7 (fed), jejunum pH is 4.4–6.6, ileum pH is 6.8–8.6, and colon pH is 5–8

. What are examples of routes of drug administration?

Oral (po), intravenous (iv), intramuscular (im), subcutaneous (sc), sublingual, topical, transdermal, inhalational, intrathecal, nasal, and rectal

. What is drug distribution?

Where a drug goes after absorption, dissolving initially in blood plasma and diffusing through tissues dissolved in extracellular fluid (ECF)

. What factors interfere with drug distribution?

Circulation quality, binding to blood plasma proteins like albumin, partitioning into fat stores, and crossing the blood-brain barrier (BBB)

. How does plasma protein binding (e.g., Albumin) affect drugs?

Drug molecules bound to albumin are trapped in the blood and remain biologically inactive

. How does fat partitioning affect drug activity?

Drugs dissolved and partitioned into body fat stores are not active

. What is the Volume of Distribution (Vd)?

The apparent volume the drug would occupy if the total amount administered was dissolved in solution at the same concentration found in blood plasma

. What is the formula for Volume of Distribution (Vd)?

Vd = Amount of drug administered / Concentration of drug in blood plasma

. What does a high Volume of Distribution (Vd) indicate?

More of the drug has left the plasma and entered body tissues or fat

. What is the typical blood plasma volume of an 80 kg human?

Around 4 litres, or 0.05 litres per kilogram

. Why are some drugs designed for localized rather than systemic action?

To keep the drug in a specific body compartment and minimize systemic side effects

. How does cetirizine avoid causing drowsiness?

It is a non-sedating antihistamine designed not to cross the blood-brain barrier (BBB)

. Where does drug metabolism primarily occur?

In the liver, where enzymes break down drugs into metabolites

. Can drug metabolites be active or toxic? Give examples.

Yes, codeine is metabolised to active morphine, while paracetamol toxicity is caused by a harmful metabolite

. What are the main routes of drug excretion?

Primarily urine via the kidneys, as well as faeces, sweat, bile, and breath

. What is drug half-life (t½)?

The time required for the drug concentration in blood plasma to fall by half

. What pattern does plasma concentration follow after an intravenous bolus injection?

A monoexponential decline

. What is drug clearance?

The volume of blood plasma cleared of the drug per unit of time

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