Antitussives and Expectorants in Pharmacology

Upper Respiratory Tract Disorders

• Inflammatory disorders: rhinitis, sinusitis, tonsillitis, and common cold
• Viral or bacterial infections cause excessive mucus production and irritation of nasal mucosa
• Symptoms: sneeze and cough reflex, nasal congestion, and mucosal irritation

Cough Physiology

• Cough is a physiological and protective reflex to clear airways
• Can be a sign of disease, such as infections, asthma, or pulmonary tumors
• Two types of cough:
  • Non-productive cough: viral infection, dry cough, no excessive mucus production, can be treated with cough suppressants
  • Productive cough: bacterial infections, excessive mucus production, coughing helps clear airways, cough suppression is harmful

Antitussive Drugs

• Used to stop or reduce coughing, suppress cough reflex by direct action on the CNS
• Only used for non-productive cough, not for productive cough
• Examples: Corticosteroids (Beclomethasone, Mometasone, Flunisolide)

Mucolytic Drugs

• Reduce viscosity of sputum and respiratory secretions, making it easier to cough up
• Examples: Bromhexine, Ambroxol, Acetylcysteine, Carbocysteine

Lower Respiratory Tract Disorders

• COPD: progressive lung disease causing breathing problems, associated with lung inflammation
• Asthma: episodic obstruction of respiratory passage, characterized by wheezing, shortness of breath, and difficulty breathing

Antiasthma Drugs

• Bronchodilators:
  • β-receptor agonists: Salbutamol, Terbutaline, Salmeterol, Formoterol
  • Xanthine derivatives: Theophylline, Aminophylline
• Leukotriene antagonists: block leukotriene effects, preventing bronchospasm, inflammation, and mucus secretion

Expectorants

• Help remove mucus by stimulating secretory glands, loosening and thinning sputum
• Used in non-productive and chronic cough
• Examples: Guaifenesin, Potassium iodide

Histamines and Antihistamines

• Histamine: released in response to allergic reactions, causing histamine effects (congestion, runny nose, watery eyes)
• Antihistamines: bind to H1 histamine receptors, preventing histamine effects
• Used to relieve cold symptoms, perennial or seasonal allergic rhinitis, allergic reactions
• Examples: Diphenhydramine, Fexofenadine, Loratadine

Nasal Congestion and Decongestants

• Nasal congestion: dilation of nasal blood vessels, transudation of fluid into tissue spaces, and swelling of nasal cavity
• Causes: allergy, infection, inflammation
• Decongestants:
  • Adrenergics: stimulate α-adrenergic receptors, causing vasoconstriction
  • Examples: Naphazoline, Oxymetazoline, Phenylephrine

This quiz covers the types of antitussives, including opioids and non-opioids, and expectorants that help remove mucus from the respiratory tract. Learn about their mechanisms and uses in treating coughs.