Respiratory Pharmacology and Support: Antihistamines, NSAIDs, and Physiotherapy

What are the three main categories of the 'Therapeutic Arsenal' in respiratory management?

Antihistamines, NSAIDs, and non-pharmacological support.

Antihistamines are primarily used for management mediated by which antibody?

IgE (Immunoglobulin E).

What is the primary pharmacological goal of NSAIDs in respiratory care?

Modulation of inflammation and pain.

Non-pharmacological support focuses on which two physiological processes?

Mechanical ventilation and oxygenation.

Which enzyme do NSAIDs inhibit to reduce prostaglandin synthesis?

Cyclooxygenase (COX).

In the pathophysiology of histamine, which cells release histamine after encountering an antigen?

Mast cells and basophils.

How does histamine release affect vascular diameter, and what is the clinical result?

It causes vasodilation, resulting in nasal congestion.

What clinical symptom results from histamine-induced increased vascular permeability?

Rhinorrhea.

Histamine stimulation of sensory nerves leads to which two primary symptoms?

Sneezing and pruritus (itching).

What is the effect of histamine on bronchial smooth muscle?

Smooth muscle contraction (bronchospasm).

What is the specific mechanism of action for antihistamines at the H₁ receptor?

They act as inverse agonists, stabilizing the inactive receptor conformation.

Why do antihistamines have a 'highly limited effect' on acute asthma exacerbations?

They have minimal effect on established bronchospasm.

Which specific vascular and capillary effects do antihistamines successfully attenuate?

Vasodilation and capillary permeability.

List four examples of first-generation antihistamines.

Diphenhydramine, chlorpheniramine, hydroxyzine, and promethazine.

What characteristic of first-generation antihistamines allows for high Blood-Brain Barrier (BBB) penetration?

They are lipophilic.

First-generation antihistamines show low receptor selectivity, interacting with which three non-histamine systems?

Muscarinic, α-adrenergic, and serotonergic systems.

What are the two primary safety concerns/side effects of first-generation antihistamines?

CNS depression and anticholinergic effects.

List three examples of second-generation antihistamines.

Loratadine, cetirizine, and desloratadine.

How does the Blood-Brain Barrier (BBB) penetration of second-generation antihistamines compare to the first generation?

It is minimal.

What is the primary receptor focus of second-generation antihistamines?

Peripheral H₁ receptors.

List three examples of third-generation antihistamines.

Fexofenadine, levocetirizine, and desloratadine.

What is the level of Blood-Brain Barrier (BBB) penetration for third-generation antihistamines?

Negligible.

What safety advantage do third-generation antihistamines have over previous generations regarding the heart?

Minimal cardiotoxic potential.

What are the primary clinical indications for antihistamines?

Seasonal/perennial allergic rhinitis and allergic conjunctivitis.

In what secondary respiratory condition is antihistamine use considered an 'adjunctive' therapy?

Mild allergic asthma.

For which specific symptoms of allergic rhinitis are antihistamines highly effective?

Sneezing and rhinorrhea.

How effective are antihistamines for treating nasal congestion?

They have limited efficacy.

Which age group is at risk for 'paradoxical excitation' from antihistamines?

Pediatrics.

Why must antihistamines be used with caution in the elderly?

Risk of CNS depression and impaired cognition leading to falls.

Antihistamines are contraindicated in which specific ocular condition?

Narrow-angle glaucoma.

What is the clinical term for the dry mouth caused by the anticholinergic burden of antihistamines?

Xerostomia.

Caution is advised when using antihistamines in patients with which bladder-related condition?

Prostatic hyperplasia (due to urinary retention risk).

What is the 'constitutive' or 'protective' role of the COX-1 enzyme?

Gastric mucosal protection, platelet aggregation, and renal blood flow regulation.

What is the 'inducible' or 'inflammatory' role of the COX-2 enzyme?

Synthesis of prostaglandins mediating inflammation, pain sensitization, and fever.

Which medication is an irreversible salicylate that inhibits COX enzymes for the lifespan of a platelet?

Aspirin (Acetylsalicylic acid).

List four examples of traditional non-selective NSAIDs.

Ibuprofen, diclofenac, naproxen, and indomethacin.

What is the primary toxicity risk associated with traditional non-selective NSAIDs?

Higher GI (gastrointestinal) toxicity risk.

List two examples of preferential COX-2 inhibitors.

Meloxicam and etodolac.

List two examples of selective COX-2 inhibitors (Coxibs).

Celecoxib and etoricoxib.

Selective COX-2 inhibitors carry an increased risk for which type of adverse events?

Prothrombotic (cardiovascular) events.

In NSAID toxicity, why does blocking COX-1 lead to peptic ulcer disease?

It reduces gastric mucosal protection.

What is the renal consequence of NSAID-induced decreased perfusion?

Sodium/water retention and acute kidney injury risk.

NSAIDs are generally contraindicated during which stage of pregnancy?

The third trimester.

What does the acronym NERD stand for in the context of NSAID toxicity?

NSAID Exacerbated Respiratory Disease.

What is the pathophysiology behind NERD-induced bronchospasm?

Inhibiting the COX pathway shunts arachidonic acid toward increased leukotriene production.

List three interventions for nasal mucosal hydration.

Isotonic/hypertonic saline, nasal gels, and humidified air.

How does nasal mucosal hydration assist in allergic rhinitis?

It removes allergens and mediators while improving mucociliary clearance.

List four techniques used in respiratory physiotherapy.

Chest percussion, postural drainage, positive expiratory pressure (PEP) devices, and diaphragmatic breathing.

Respiratory physiotherapy reduces the risk of _____ in patients with COPD or cystic fibrosis.

Atelectasis

What is the primary goal of oxygen therapy?

To correct arterial oxygen deficiency (PaO₂) and improve tissue oxygen delivery.

Which oxygen delivery device allows for the most precise FiO₂ control?

Venturi Mask.

List the four oxygen delivery systems in order of typical clinical progression.

Nasal Cannula, Simple Face Mask, Venturi Mask, High-Flow Nasal Systems.

In chronic CO₂ retention (COPD) patients, excessive oxygen can suppress the _____.

Hypoxic respiratory drive

What core protocol is essential during oxygen therapy to prevent adverse outcomes?

Continuous monitoring of oxygen saturation and arterial blood gases.

For uncomplicated seasonal allergic rhinitis, what generation of antihistamine is preferred?

Second or third generation.

Why are antihistamines considered of limited utility in viral URIs?

The symptoms are not IgE-mediated.

In a patient with asthma and nasal polyposis, NSAIDs should be _____.

Strictly avoided

Why should first-generation antihistamines be avoided in severe COPD exacerbations?

They cause anticholinergic drying of secretions.

Which non-pharmacological intervention is recommended for airway clearance in asthma patients with mucus retention?

Respiratory physiotherapy.

In a severe COPD exacerbation with hypoxemia, which oxygen mask is preferred to avoid CO₂ retention?

Titrated Venturi Mask.

How do NSAIDs affect blood pressure?

They can cause hypertension due to sodium and water retention.

Which specific NSAID class is most associated with an imbalance between thromboxane and prostacyclin?

Selective COX-2 inhibitors.

What is the mechanism of isotonic saline in managing allergic rhinitis?

It restores moisture and reduces epithelial microtrauma.

What is the therapeutic window goal for oxygen therapy?

To stay within the 'Optimal Range' and avoid the 'Risk Zone' of toxicity or drive suppression.

Identify the primary cardiovascular risks associated with NSAID toxicity.

Hypertension, MI (Myocardial Infarction), and stroke risk.