22. Drugs for Cough

• Expectorants - Stimulate the production of a watery, less viscous mucus, hence enhance its clearance.
• Expectorants

  • Mucokinetics: Enhance bronchial secretion, act on cilia and increase mucociliary clearance
  • Mucolytics:  reduce the viscosity (liquefaction) of respiratory secretion without increasing amount.
• Expectorants - For productive cough

  • Mucokinetics - Guaifenesin
  • Mucolytics - Acetylcysteine
• Acetylcysteine MOA

  • reduces disulfide bridge that binds to glycoprotein to other protein such as
  • albumin
  • secretory IgA
• Acetylcysteine -

  makes the sputum less viscid

  breaking disulfide bonds
• Acetylcysteine used in Cystic fibrosis
• Mucolytics - Dornase alfa MOA

  • hydrolyzes DNA present in sputum of cystic fibrosis pts
• Dornase alfa uses - approved for standard therapies for cystic fibrosis to improve pulmonary function
• Antitussives use for dry unproductive cough
• Antitussives MOA

  • act in the CNS to raise the threshold of cough center
  • act peripherally in respiratory tract to reduce cough impulse
• opioid derivatives most commonly used as antitussives are

  • (Dextro) dextromethorphan
  • Codeine
• antitussive

  • low dose - analgesia
  • high dose - CNS effects
• Dextro C/I in pts taking monoamine oxidase inhibitor
• Dextro MOA

  • desensitizes medullary cough
  • function as NMDA antagonist
  • 5HT and NE transporter inhibitor
• Dextro use in acute debilitating cough
• Dextro ADE

  • increase the risk of serotonin syndrome when combine with SSRI (fluoxetine) or MAOI
• Dextro abused in high dose - euphoria or hallucination
• H1 blocker used for allergic rhinitis
• Nasal Decongestants ADE

  • rebound congestion hyperemia due to desensitization of a1 receptor
  • atrophic rhinitis
  • anosmia
• Nasal Decongestants C/I in?

  • hypertension
  • MAOI
• Nasal decongestant (a agonist) use for allergic rhinitis