Antitussives

Antitussives are drugs that suppress the cough reflex by acting on the cough center or peripheral pathways to relieve dry cough.

Purpose:

• Used in dry, irritating, non-productive cough to suppress the cough reflex.

Antitussives

• Function: Suppress or reduce the urge to cough
• Use: For non-productive (dry) coughs
• Mechanism: Act on the cough center in the brain or reduce sensitivity
• Examples:
  • Central-acting: Dextromethorphan, Codeine
  • Peripheral-acting: Benzonatate

Types of Antitussives

1. Central Acting

   • Act on the cough center in the medulla to suppress the reflex.

     1. Opioid

        • Examples: Codeine, Pholcodine
        • Mechanism: Act on μ-opioid receptors in the brainstem → suppress cough center
        • Use: Severe, dry cough
        • Caution: Can cause sedation, constipation, respiratory depression, and dependence

     2. Non-opioid

        • Examples: Dextromethorphan, Noscapine
        • Mechanism: Suppress cough center without significant opioid-like effects
        • Use: Safer alternative to codeine, widely used in OTC cough syrups
        • Note: Dextromethorphan can cause hallucinations in high doses (abuse potential)

2. Peripheral Acting

   • Examples: Benzonatate, Menthol, Honey
   • Mechanism: Decrease the sensitivity of cough receptors in the respiratory tract
   • Use: Soothing action for throat irritation (lozenges, syrups)

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