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Introduction to Respiratory Care Pharmacology

Pharmacology and the Study of Drugs

  • Focus: Respiratory care pharmacology as a subfield of pharmacology.
  • Key terms and relationships:
    • Pharmacy
    • Pharmacognosy
    • Pharmacogenetics
    • Therapeutics
    • Toxicology
  • Core definition:
    • A drug is any chemical that alters the organism’s functions or processes.
  • Purpose of this chapter: Build foundational understanding for prescribing, interpreting drug actions, and regulatory context in respiratory care.

Naming Drugs

  • Five different names for each drug:
    • Chemical name
    • Code name
    • Generic name
    • Official name
    • Trade name (brand name)
  • Brand name vs generic naming (example concepts from slides):
    • Brand name vs generic name: active ingredient is the same while packaging, dosage form, and price may differ.
    • Brand products may have different labeling and marketing; generics are typically lower in cost.
    • Insurance coverage can differ between brand-name and generic products.
    • FDA testing ensures therapeutic equivalence between brand-name and generic products.
  • Example concepts illustrated in slides:
    • Benadryl (brand) vs Diphenhydramine HCl 25 mg (generic/active ingredient)
    • Tylenol (brand) vs acetaminophen (generic) with examples like Extra Strength Tylenol (500 mg caplets)
    • Packaging attributes such as caplets/tablets, color, and size may differ while active ingredient remains the same.
    • Notation on packaging may include identifiers (e.g., MDC 11673-838-5) for reference.
  • Practical implication: When substituting generics, ensure active ingredient and strength match; reimbursement and labeling considerations may guide substitution.

Sources of Drug Information

  • Key reference works and databases:
    • United States Pharmacopeia-National Formulary (USP-NF)
    • Physician’s Desk Reference (PDR)
    • Goodman & Gilman’s The Pharmacological Basis of Therapeutics (14th edition) [note: edition cited in slides; current editions exist]
    • Basic & Clinical Pharmacology (15th edition)
    • Drug Facts and Comparisons (Facts & Comparisons)
    • NDC database (National Drug Code)
  • Practical use: These sources guide dosing, interactions, safety, and regulatory status for clinicians.

Sources of Drugs

  • Primary sourcing generally through chemical synthesis.
  • Other natural sources contribute to drug development:
    • Animal sources: e.g., thyroid hormone, insulin, pancreatic dornase
    • Plant sources: e.g., khellin (Ammi visnaga), atropine (belladonna alkaloid), digitalis (foxglove), reserpine, volatile oils of eucalyptus, pine, anise
    • Mineral sources: e.g., copper sulfate, magnesium sulfate (Epsom salts), mineral oil (liquid hydrocarbons)
  • Significance: Diversity of sources informs pharmacology, toxicity, and therapeutic options.

Process of Drug Approval in the United States

  • Descriptive overview:
    • Lengthy and expensive process with multiple phases
    • Steps include chemical isolation and identification, followed by animal studies, then human testing
    • Investigational New Drug (IND) approval is required to proceed to human trials
    • Phases: Phase 1, Phase 2, Phase 3
    • New Drug Application (NDA) submission follows successful trials
    • Post-approval: a reporting system for the first 6 months after market entry
  • Real-world relevance: Regulatory framework governs safety, efficacy, and timeliness of new therapies in respiratory care.

Major Steps in the Process of Marketing a Drug in the United States

  • Steps (high-level list mirroring slides):
    • Chemical isolation and identification
    • Animal studies
    • General effects (preclinical safety and pharmacology)
    • Special effects on organ systems
    • Toxicology studies
  • Purpose: Establish a comprehensive safety and efficacy profile before widespread clinical use.

Investigational New Drug (IND) Approval

  • Phase 1: Small number of healthy subjects to assess safety and pharmacokinetics.
  • Phase 2: Small number of subjects with disease to assess efficacy and dosing.
  • Phase 3: Large, multicenter studies to confirm efficacy and monitor adverse effects in diverse populations.
  • Goal: Determine whether a drug should proceed toward NDA submission.

Alphanumeric Coding System of the FDA

  • Coding categories and meanings:
    • 1 = new chemical entity
    • 2 = new salt form
    • 3 = new dosage form
    • 4 = new combination
    • 5 = generic drug
    • 6 = new indication
  • Practical use: Helps organize and track drug development, formulations, and regulatory status.

Therapeutic Potential

  • Designations indicating therapeutic gain:
    • $A$ = important (significant therapeutic gain over other drugs)
    • $AA$ = important therapeutic gain; indicated for patients with AIDS; fast-track
    • $B$ = modest therapeutic gain
    • $C$ = important options; little or no therapeutic gain
  • Implication: Guides development priorities, regulatory review, and clinical use considerations.

Orphan Drugs

  • Definition: A drug or biologic product for the diagnosis or treatment of a rare disease.
  • Rare disease criterion: affects fewer than <200{,}000 persons in the United States.
  • Economic criterion: qualifies as an orphan drug if there is no reasonable expectation of recovering the cost of drug development.
  • Note: Table 1-2 in the source contains examples of orphan drugs.

The Prescription

  • Parts of a prescription:
    • Patient name, address, date
    • Rx (the prescription blank)
    • Inscription (drug and strength)
    • Subscription (dispense quantity and instructions to pharmacist)
    • Signature (prescriber’s signature)
    • Name of prescriber
    • Generic substitution indicator (whether generic substitution is permitted or required)
    • Physician’s indication regarding substitution
  • Example from slides:
    • 1. Name; 2. Address; 3. R; 4. Albuterol 4 mg tabs; No. 120; [Directions on preparing]; 5. Sig: Take 1 p.o. QID; 6. A. Gleason M.D.; ☐ Generic substitute permitted
  • Practical note: The prescription format ensures safety, traceability, and appropriate dispensing.

Over-the-Counter Drugs

  • Definition: Do not require a prescription.
  • Caution: Can be hazardous if misused.
  • Practical implication: Self-treatment using OTCs can mask or complicate a serious medical condition.

Respiratory Care Pharmacology: An Overview

  • Route of administration: Aerosolized agents given by inhalation.
  • Five advantages of inhaled therapy:
    • \text{Smaller dose}
    • \text{Fewer side effects}
    • \text{Rapid onset}
    • \text{Targets respiratory system}
    • \text{Painless, relatively safe}
  • Rationale: Inhalation delivers medications directly to the lungs with favorable pharmacokinetics.

Related Drug Groups in Respiratory Care

  • Major categories represented in respiratory care:
    • Antiinfective agents
    • Neuromuscular blocking agents
    • Central nervous system agents
    • Antiarrhythmic agents
    • Antihypertensive and antianginal agents
    • Anticoagulant and thrombolytic agents
    • Diuretics
  • Practical relevance: These drug groups are frequently encountered in respiratory therapy practice and require understanding of indications, contraindications, and interactions.