How to manage an intractable dry cough?

Management of Intractable Dry Cough

For patients with intractable dry cough, a stepwise approach starting with dextromethorphan at higher therapeutic doses (up to 60 mg) is recommended as first-line treatment, followed by consideration of opioids such as morphine for refractory cases, particularly in palliative settings. 1, 2

First-Line Treatments

• Dextromethorphan is the preferred initial treatment for dry cough due to its superior efficacy and better side effect profile compared to codeine and other opioids 1, 2
• Maximum cough reflex suppression occurs at 60 mg doses with prolonged effect (higher than typical OTC preparations) 1
• Menthol by inhalation (as crystals or proprietary capsules) provides acute, short-lived cough suppression and can be used as an adjunct therapy 1, 2
• Simple home remedies like honey and lemon mixtures can provide symptomatic relief and should be considered before prescription medications 1, 2
• Adequate hydration helps manage symptoms and should be encouraged in all patients 2

Second-Line Options

• First-generation sedating antihistamines can be particularly helpful for nocturnal cough when sleep disruption is a significant issue 1, 3
• For patients with GERD-related cough, an intensive treatment regimen should include:
  • Antireflux diet (≤45g fat/24h, avoiding coffee, tea, soda, chocolate, mints, citrus, tomatoes, alcohol)
  • Acid suppression with proton pump inhibitors
  • Prokinetic therapy 1

Refractory Cough Management

• For intractable cough not responding to first and second-line treatments, opioids should be considered, particularly in palliative settings 1, 4
• Morphine (5-10 mg slow-release formulation) has shown efficacy for refractory cough with significant improvement in quality of life 1, 5
• Nebulized morphine (5-15 mg mixed with 3 mL normal saline) can be effective for intractable cough in advanced cancer with fewer systemic side effects 5
• Novel agents such as paroxetine (10-20 mg) have shown promising results for intractable cough in cancer patients, with 71% experiencing moderate to major reduction in cough severity 6
• Gabapentin may be considered for refractory chronic cough based on recommendations for unexplained chronic cough 1
• Multimodality speech pathology therapy that includes cough suppression techniques, vocal hygiene, and psychoeducational counseling can be beneficial 1

Special Considerations

• In patients with lung cancer experiencing cough, an initial trial with demulcents (butamirate linctus, simple linctus, or glycerol-based linctus) should be attempted before moving to opioid derivatives 1
• For opioid-resistant cough in lung cancer, peripherally acting antitussives like levodropropizine may be considered 1
• When using opioids for cough control, start with lower doses and titrate to effect while monitoring for side effects:
  • Morphine: 5 mg (single-dose trial) followed by 5-10 mg slow-release bid if effective
  • Hydrocodone: 5 mg bid
  • Dihydrocodeine: 10 mg tid 1

Monitoring and Follow-up

• When prescribing opioids for symptom control, reassess benefits and risks at 1 week and then monthly before continuing 1
• Monitor for common side effects of opioids including constipation, drowsiness, and respiratory depression 4
• For patients with chronic cough, assess impact on quality of life using validated tools 1

When to Seek Further Medical Attention

• Patients should seek immediate medical attention if they experience:
  • Hemoptysis (coughing up blood)
  • Progressive breathlessness
  • Prolonged fever and systemic symptoms
  • Worsening of underlying conditions (COPD, heart disease, diabetes, asthma)
  • Symptoms persisting beyond three weeks despite treatment 1

Remember that intractable cough significantly impacts quality of life and warrants aggressive symptomatic management when specific treatments for underlying causes have failed 1, 4.