Pharmacology study sheet-Kopp 11-14-25

Pharmacology Basics in Respiratory Care

Pharmacology plays a crucial role in respiratory care; expect several questions on the exam related to respiratory medications. This section focuses on the key pharmacological concepts necessary for exam success with an emphasis on essential drug categories and their functions rather than an exhaustive list of all respiratory drugs.

Bronchodilators

Bronchodilators are medications that alleviate bronchoconstriction by relaxing smooth muscle tissue in the airways.

  • Beta-2 Adrenergic Agonists

    • Short-acting (Rescue inhalers)

    • Function: Provide immediate relief from bronchospasms.

    • Example: Albuterol (Ventolin, Proventil).

    • Long-acting (Maintenance therapy)

    • Function: Used for long-term control, beneficial for conditions like COPD and asthma.

    • Example: Arformoterol (Brovana).

  • Anticholinergic Bronchodilators

    • Function: Block acetylcholine to prevent bronchoconstriction, primarily utilized for COPD.

    • Short-acting: Ipratropium bromide (Atrovent).

    • Long-acting: Tiotropium bromide (Spiriva).

  • Methylxanthines (Phosphodiesterase Inhibitors)

    • Function: Increase cyclic AMP levels to encourage bronchodilation but are less commonly employed due to side effects.

    • Example: Theophylline (Aminophylline).

Anti-Inflammatory Agents

These medications are essential for reducing airway inflammation relevant to asthma and COPD management.

  • Corticosteroids

    • Inhaled: Utilized for long-term control.

    • Examples: Budesonide (Pulmicort), Fluticasone (Flovent), Triamcinolone (Azmacort).

    • Systemic (Oral/IV): Administered for severe exacerbations.

    • Example: Prednisone.

  • Leukotriene Modifiers

    • Function: Block leukotrienes to decrease inflammation and bronchoconstriction.

    • Example: Montelukast (Singulair).

  • Mast Cell Stabilizers

    • Function: Prevent histamine release, mitigating inflammation and allergic responses.

    • Example: Cromolyn sodium.

Mucolytics & Other Respiratory Medications

Mucolytic Agents

  • Function: Assist in breaking down and thinning mucus for better clearance.

  • For thick secretions: Acetylcysteine (Mucomyst).

  • For cystic fibrosis: Dornase alfa (Pulmozyme).

Pulmonary Vasodilators

  • Function: Address pulmonary hypertension to enhance blood flow in the lungs.

  • Examples: Nitric Oxide, Iloprost.

Hypertonic Saline

  • Function: Aids in mobilizing secretions in conditions such as cystic fibrosis and bronchiectasis.

Albuterol (SVN) Administration

  • Standard Dose: 0.5 mL (2.5 mg) via nebulizer.

  • Frequency: 3–4 times per day.

Selecting the Most Appropriate Aerosol Delivery Device

Understanding aerosol delivery devices is essential for clinical practice.

Three Main Aerosol Delivery Devices

  1. Small-Volume Nebulizer (SVN)

  2. Metered-Dose Inhaler (MDI)

  3. Dry Powder Inhaler (DPI)

General Guideline

  • MDIs and DPIs are preferred over SVNs for efficiency and convenience, though some patients may require an SVN due to difficulty in using MDIs or DPIs correctly.

Important Considerations for Each Device

  • Metered-Dose Inhaler (MDI)

    • Requires hand-breath coordination for activation while inhaling.

    • For patients unable to coordinate, consider DPI or SVN.

  • Dry Powder Inhaler (DPI)

    • Does not necessitate hand-breath coordination.

    • Requires deep, fast inhalation (40–60 L/min) for effective medication delivery.

    • If a patient cannot achieve this inspiratory flow, opt for MDI or SVN.

Key Anti-Infective Agents

  1. Tobramycin (TOBI)

    • Class: Aminoglycoside antibiotic

    • Indication: Treats Pseudomonas aeruginosa infections in cystic fibrosis.

    • Administration: Inhaled via nebulizer for localized lung treatment.

  2. Penicillin

    • Class: Beta-lactam antibiotic

    • Indication: Effective against gram-positive bacteria (e.g., Streptococcus, Staphylococcus).

    • Administration: Oral or intravenous.

  3. Gentamicin

    • Class: Aminoglycoside antibiotic

    • Indication: Targets gram-negative organisms (e.g., E. coli, Pseudomonas aeruginosa).

    • Administration: Intravenously or inhaled.

  4. Ribavirin (Virazole)

    • Class: Antiviral agent

    • Indication: Treats respiratory syncytial virus (RSV) in infants/children.

    • Administration: Requires a SPAG nebulizer.

  5. Pentamidine (NebuPent)

    • Class: Antiprotozoal agent

    • Indication: Prevents and treats Pneumocystis jirovecii pneumonia (PCP) in HIV/AIDS patients.

    • Administration: Respirgard II nebulizer to prevent healthcare worker exposure.

  6. Zanamivir (Relenza)

    • Class: Antiviral agent

    • Indication: Treatment and prevention of influenza A and B.

    • Administration: Inhaled via DPI.

Diuretic Agents

Overview

Diuretics increase urine production, aiding the elimination of excess water and sodium, primarily to manage fluid overload (hypervolemia).

Common Conditions That Require Diuretics

  • Congestive Heart Failure (CHF): Inefficient heart pumping leads to fluid buildup.

  • Pulmonary Edema: Excess fluid in the lungs causes severe breathlessness.

Indications for Diuretic Administration

  • Indicative signs of fluid overload necessitating diuretics include:

    • Peripheral edema: Swelling in extremities.

    • Jugular venous distention (JVD): Bulging neck veins due to increased central venous pressure.

    • Crackles on auscultation: Fluid in the lungs, typically at bases.

    • Shortness of breath: Due to fluid retention.

Key Exam Tip

  • Do not confuse wheezing with bronchospasm: For wheezing caused by fluid overload, a diuretic is necessary, not a bronchodilator.

Endotracheal Instillation

Overview

Endotracheal instillation is a method for administering medications directly into the trachea using an endotracheal tube, especially vital in emergencies without IV access.

NAVEL Mnemonic

  • N: Naloxone (Narcan) – Opioid overdose reversal.

  • A: Atropine – Addresses bradycardia.

  • V: Vasopressin – Boosts blood pressure during cardiac arrest.

  • E: Epinephrine – Used in cardiac arrest/anaphylaxis.

  • L: Lidocaine – Treats ventricular arrhythmias.

Additional Medication

  • Exogenous Surfactant: Given via instillation in premature infants for neonatal respiratory distress syndrome (RDS) to improve lung compliance.

Important Administration Guidelines

  • Dosing Adjustment: Medications via ET instillation typically require a higher dose (2 to 2.5 times normal IV dose).

  • Dilution: Drugs must be diluted with 10 mL of saline or sterile water before use.

  • Follow with ventilation: Manual ventilation is critical post-instillation to ensure medication reaches the lungs.

Drug Overdose

Overview

A drug overdose occurs when a patient consumes an excess of a substance, leading to potential life-threatening conditions, including respiratory failure.

Exam Tip

  • Expect exam questions on treating opioid overdoses.

Opioid Overdose Risks

Opioid overdose is a leading cause of drug fatalities. Common opioids include:

  • Morphine

  • Heroin

  • Oxycodone

  • Fentanyl

  • Prescription painkillers

Recognizing Opioid Overdose

Signs include:

  • Severe respiratory depression or apnea

  • Altered mental status/unresponsiveness

  • Pinpoint pupils (miosis)

  • Bradycardia and hypotension.
    In critical cases, intubation and mechanical ventilation may be required.

Key Treatment: Naloxone (Narcan)

  • Function: Antidote for opioid overdose.

  • Mechanism: Displaces opioids from receptors to reverse effects.

  • Administration: IV, IM, subcutaneous injection, or intranasal spray.

  • Repeat dosing may be necessary due to its shorter half-life compared to some opioids.

Xanthine Drugs

Overview

Xanthine drugs increase cyclic AMP (cAMP) levels in smooth muscle, promoting bronchodilation. Although not as commonly prescribed, it is vital to know their applications.

Types of Xanthine Drugs

  • Theophylline

  • Caffeine

Primary Uses

  1. Apnea of Prematurity: Theophylline and caffeine act as respiratory stimulants for premature infants, increasing respiratory drive.

  2. Cheyne-Stokes Breathing: Theophylline may help reduce occurrences of this abnormal breathing.

Reminder: Cheyne-Stokes Breathing

  • Cyclic breathing pattern marked by gradual increases and decreases in tidal volume, with periods of apnea. Common in patients with stroke, head trauma, or CHF.

Exam Tip

  • Anticipate questions concerning xanthine drugs related to apnea of prematurity and Cheyne-Stokes breathing.

  • Monitor theophylline levels closely due to a narrow therapeutic range with potential toxicity.

Neuromuscular Blocking Agents (NMBAs)

Overview

NMBAs are paralytics used for intubation and mechanical ventilation. They do not provide sedation or pain relief, requiring concurrent administration of a sedative and analgesic.

Two Types of NMBAs

  1. Depolarizing NMBA

    • Succinylcholine: Rapid onset and short duration, ideal for rapid sequence intubation (RSI).

    • Contraindications: Hyperkalemia, burns, neuromuscular disorders due to potassium shift risk.

  2. Non-Depolarizing NMBAs

    • Examples: Rocuronium, Vecuronium, Pancuronium.

    • Reversal agents: Neostigmine (with atropine) or Sugammadex (specific to rocuronium/vecuronium).

Exam Tip

  • If a paralyzed patient shows distress, such as tachycardia or hypertension, ensure they receive additional sedation and pain management.

  • Always confirm adequate sedation for paralyzed patients before assuming comfort.
    Understanding NMBA applications will prepare students for exam inquiries on paralytic agents.