Interventions in unexplained chronic cough

What evidence-based interventions, or interventions in general, can be offered to individuals with unexplained chronic cough?

Imran Satia: After going through the diagnostic algorithm of chronic cough, if you get to the diagnosis of cough hypersensitivity syndrome, or chronic idiopathic cough, or chronic refractory cough, then you essentially have 2 broad treatment options. One is medicinal and the second is nonmedicinal. We often talk to patients and offer these options.

In the medicinal option there are randomized controlled studies with morphine, gabapentin, pregabalin, and one study with amitriptyline. The morphine study suggested that a very, very low dose of morphine, 5 mg twice a day, can be effective at reducing cough. We normally advocate a trial of 2 weeks for trying this and seeing if this is effective, and in our experience it is effective in 40% to 50% of patients who get complete or partial relief. If this is not effective, then our second-line options that we have are gabapentin and pregabalin and these have been shown in randomized controlled trials to be effective.

There is a bit of difference in North America and Europe with regards to which should be the first line, whether it should be low-dose opioid-based or whether it should be pregabalin or gabapentin. In Europe, generally morphine is the first line, whereas in North America and Canada pregabalin and gabapentin are probably the first-line options, because problems with opioid toxicity and addiction are a major issue.

With regards to nonmedicinal treatment options, we find that the work done by Peter Gibson and Anne Vertigan on speech and language therapy has been very effective in reducing laryngeal hypersensitivity because many of our patients, when they describe coughing, they describe coughing emanating or being initiated from the throat area. When we see these patients and we undergo nasal endoscopy or bronchoscopy we notice that there may be a lot of laryngeal tension in [the area of vocal cords]. Therefore, they undergo a period of speech and language therapy, which in our experience has also been quite useful. Along with medicinal options, it is a possibility.

Apart from those options, there is some very minimal data to suggest amitriptyline 10 mg at night might be effective.

Those are the current treatment options which have been documented in the European Respiratory Society (ERS) guidelines along with the American College of Chest Physicians (ACCP) guidelines.