Drugs Affecting the Respiratory System

Bronchodilators

• Relax bronchial muscles, leading to expanded bronchial airways.
• Types include beta-2 adrenergic agonists, methylxanthines, and anticholinergics (inhaled).

Beta-2 Adrenergic Agonists

• Usage: Effective in treating asthma and COPD; targets bronchospasm and bronchoconstriction.
• Key drugs:
  • Albuterol (short-acting)
  • Salmeterol (long-acting)
• Mechanism: Activate beta-2 receptors to induce bronchodilation.
• Contraindications: Not recommended for pregnant patients, those with tachydysrhythmias, diabetes, hyperthyroidism, heart disease, or hypertension.
• Side Effects: Noted as the 3T's – tachycardia, tremors, and difficulty sleeping.
• Monitoring: Keep an eye on cardiac dysrhythmias and respiratory status.
• Patient Education: Instruct to take inhaled beta-2 agonist before inhaled glucocorticoid and to avoid caffeine.

Methylxanthines

• Usage: Primarily used for chronic asthma and COPD management.
• Key drugs:
  • Theophylline
  • Phenytoin/rifampicin (may decrease theophylline levels)
  • Fluoroquinolones (may increase theophylline levels)
• Mechanism: Relaxation of bronchi smooth muscle, aiding in bronchodilation.
• Contraindications: Caution in pregnant individuals, children, and those with heart/renal disease, diabetes, or hypertension.
• Side Effects: Observed as SARG – seizures, arrhythmias, restlessness, and gastrointestinal upset.
• Monitoring: Continuous cardiac monitoring for dysrhythmias, respiratory status checks, and blood levels to avoid toxicity.
• Patient Education: Advise against caffeine consumption to minimize side effects.

Anticholinergics (Inhaled)

• Usage: Mainly prescribed for COPD management and occasionally for asthma.
• Key drug: Ipratropium.
• Mechanism: Blocks muscarinic receptors in the bronchi, leading to bronchodilation.
• Contraindications: Not suitable for pregnant patients, those with a peanut allergy, narrow-angle glaucoma, or benign prostatic hyperplasia (BPH).
• Side Effects: Results in severe dryness in various bodily functions (mouth, urination, sight, defecation).
• Monitoring: Watch for dry mouth symptoms and assess respiratory status.
• Patient Education: Encourage hydration and recommend sugar-free candy to relieve dry mouth.

Bronchodilators

• Function: Relax bronchial muscles to expand airways.
• Types: Include beta-2 adrenergic agonists, methylxanthines, and inhaled anticholinergics.

Beta-2 Adrenergic Agonists

• Usage: Treatment for asthma and COPD, specifically for bronchospasm and exacerbations.
• Examples: Albuterol (short-acting), Salmeterol (long-acting).
• Mechanism: Activates beta-2 receptors leading to bronchodilation.
• Contraindications: Not recommended during pregnancy or for patients with tachydysrhythmias, diabetes, hyperthyroid conditions, heart disease, or hypertension.
• Side Effects: Tachycardia, tremors, and insomnia (3T’s).
• Monitoring: Cardiac dysrhythmias and respiratory status should be monitored.
• Patient Education: Take inhaled beta-2 agonist before inhaled glucocorticoid; avoid caffeine.

Methylxanthines

• Usage: Used for chronic asthma and COPD.
• Examples: Theophylline; interactions with phenytoin/rifamp (reduce theophylline) and fluoroquinolones (increase theophylline).
• Mechanism: Relaxes bronchial smooth muscle, resulting in bronchodilation.
• Contraindications: Avoid in pregnancy, children, and patients with heart or renal diseases, diabetes, or hypertension.
• Side Effects: Seizures, arrhythmias, restlessness, gastrointestinal upset (SARG).
• Monitoring: Requires cardiac monitoring for dysrhythmias, respiratory status, and blood levels due to risk of toxicity.
• Patient Education: Avoid caffeine.

Anticholinergics (Inhaled)

• Usage: Primarily for COPD, sometimes for asthma (bronchospasm).
• Example: Ipratropium.
• Mechanism: Blocks muscarinic receptors in the bronchi, leading to bronchodilation.
• Contraindications: Not suitable for patients with pregnancy, peanut allergies, narrow-angle glaucoma, or benign prostatic hyperplasia (BPH).
• Side Effects: Causes dryness – affecting mouth, urination, vision, and gastrointestinal function.
• Monitoring: Observe for signs of dry mouth and respiratory status.
• Patient Education: Maintain hydration; use sugar-free candy for dry mouth relief.

Anti-inflammatories

• Purpose: Reduce airway inflammation.
• Classes: Include glucocorticoids and leukotriene modifiers.

Glucocorticoids

• Usage: Long-term and short-term management of asthma.
• Examples: Prednisone, Beclomethasone.
• Mechanism: Prevents inflammation and mucus production; reduces edema.
• Contraindications: Avoid in pregnancy, live vaccines, systemic infections, diabetes, renal diseases, and hypertension.
• Side Effects: Potential for speech issues, hoarseness, mood changes, sleep disturbances, candidiasis, osteoporosis, hyperglycemia, and increased infection risk.
• Monitoring: Track blood glucose levels, daily weight, and signs of infection.
• Patient Education: Rinse mouth after use; do not stop abruptly; take after inhaled beta-2 agonists; use nystatin for candidiasis.

Leukotriene Modifiers

• Usage: Long-term treatment for asthma.
• Example: Montelukast.
• Mechanism: Suppresses leukotrienes to reduce inflammation, bronchoconstriction, airway edema, and mucus production.
• Contraindications: Avoid in pregnancy and renal disease.
• Side Effects: May cause depression, suicidal ideation, and liver injury.
• Monitoring: Assess mental and respiratory status.
• Patient Education: Take at bedtime on an empty stomach, as food may decrease absorption.