Pharmacology for Respiratory Care — Drug Action and Administration

A set of QUESTION_AND_ANSWER flashcards covering key concepts from the pharmacology notes for respiratory care, including drug definitions, naming conventions, sources, approval processes, prescription components, OTC drugs, drug action, pharmacokinetics, routes of administration, inhaled drug kinetics, receptors, signaling, dose-response, and common pharmacology terms.

What are medicinal drugs and what are their main purposes?

Substances that treat, prevent, or diagnose disease; they can also modify physiological functions.

Name the five types of drug names and what each represents.

Chemical name (chemical structure); Code name (manufacturer, often experimental); Generic/nonproprietary name (ready to market, based on structure); Official name (fully approved, usually the generic); Trade name (proprietary name by manufacturers).

What are the main sources of drugs?

Animal, Plant, and Mineral sources.

Outline the stages of the drug approval process.

Chemical identification; Animal studies; Investigational New Drug (IND) approval; Phase 1 (small, healthy); Phase 2 (small, with disease); Phase 3 (large, multicenter); New Drug Application (NDA).

What are the four main parts of a prescription and what does each contain?

Superscription: order to pharmacist; Inscription: drug name and quantity; Subscription: recipe for pharmacist; Signa (sig): patient instructions; Also include prescriber and patient information on the label.

What are Over-the-Counter (OTC) drugs and related notes?

Medications purchasable without a prescription (nonprescription); may involve generic substitutions; orphan drugs are for very small patient populations (typically <200,000) or not cost-recoverable.

Name the major categories of respiratory drugs listed.

Adrenergic; Anticholinergic; Corticosteroids; Antiasthmastic; Anti-infective; Surfactants.

What are the four processes included in pharmacokinetics?

Absorption; Distribution; Metabolism; Excretion.

What are the two main phases of drug action?

Pharmacokinetic phase (absorption, distribution, metabolism, elimination) and Pharmacodynamic phase (drug–receptor interaction and resulting effect).

What does the Drug Administration Phase cover?

Definition of administration; dosage forms; state of drug and nondrug components; compatibility with route; additives (gelatin, fillers, coatings, propellants, preservatives).

What are the main routes of administration and brief examples for each?

Enteral (GI tract, e.g., capsules/tablets); Parenteral (injections: IV, IM, SC); Transdermal (skin patches); Inhalation (MDI, DPI, etc.); Other routes (sublingual, rectal, topical, otic, ophthalmic).

What does ADME stand for in pharmacokinetics?

Absorption; Distribution; Metabolism; Excretion.

What factors affect drug absorption?

Route of administration; Blood flow to the site of absorption.

Name the major body compartments involved in distribution and their approximate volumes.

Vascular (blood) ~5 L; Interstitial fluid ~10 L; Intracellular fluid ~20 L; Fat (adipose tissue) ~14–25 L.

Where is the primary site of drug metabolism and what is the main enzyme family?

Liver; cytochrome P450 enzymes.

What is enzyme induction and what is the first-pass effect?

Enzyme induction: chronic drug use increases metabolic enzymes, speeding metabolism; First-pass effect: oral drugs are metabolized in the liver before reaching systemic circulation, reducing activity; nonoral routes can bypass this.

What is plasma clearance and what is its role in dosing?

Volume of plasma cleared of drug per unit time; used to determine maintenance dosing and dosing rate (dosing rate = Clp × target plasma concentration).

What is drug half-life?

Time required for the plasma concentration of a drug to decrease by one half.

What is the typical distribution of inhaled aerosols between oral and inhaled portions?

Oral portion ~70–90%; Inhaled portion ~10–30%; lung availability versus total availability is described by the lung/total ratio.

What are the components of G protein-coupled receptor signaling in the airways?

Drug receptor, G protein, and effector system; ligand binding activates the G protein, which modulates the effector to generate a second messenger.

What are the three components of a G protein-coupled receptor signaling complex?

Receptor, G protein (α, β, γ subunits), and effector system.

What is the sequence of events when a G protein-coupled receptor is activated?

Drug binds receptor; Receptor activates G protein (GDP → GTP on α); α-GTP dissociates from βγ and activates the effector; second messenger is produced; cellular response occurs.

Give an example of a signaling pathway for a bronchodilator mentioned in the notes.

Albuterol binds β-adrenergic receptor (Gs) → activates adenylyl cyclase → increases cAMP → bronchodilation.

Define EC50, ED50, and Maximal Effect.

EC50: concentration producing 50% of maximal response; ED50: dose producing 50% of maximal effect; Maximal effect: highest achievable effect.

What is Therapeutic Index and how is it interpreted?

TI = LD50/ED50; higher TI indicates a wider safety margin; examples: TI = 2 (LD50 5 mg, ED50 2.5 mg) or TI = 20 (LD50 50 mg, ED50 2.5 mg).

What is the difference between agonists and antagonists?

Agonists have affinity and efficacy and produce a cellular response; antagonists have affinity but no efficacy and block agonists at the receptor.

What are synergism, additivity, and potentiation in pharmacology?

Synergism: effect greater than the sum of individual effects (1+1=3); Additivity: sum of effects (1+1=2); Potentiation: one drug enhances the effect of another with the first having little or no effect (1+0=2).

What is an idiosyncratic effect?

An unusual or opposite drug reaction that is not predictable by the drug’s common action.

What is hypersensitivity in pharmacology?

Allergic or immune-mediated reaction to a drug.

What is tolerance in pharmacology?

Decreased response to a drug over time due to upregulated metabolizing enzymes or receptor changes.

What is tachyphylaxis?

Rapid decrease in responsiveness to a drug after repeated exposure.