Chronic Cough Therapies: What Works

A Report From the 4th Biannual American Cough Conference

Gary J. Stadtmauer, MD

Disclosures

June 25, 2013

The 4th biannual American Cough Conference was held in New York on June 7-8, 2013.[1] It was organized by pulmonologist Peter V. Dicpinigaitis, MD, director of the Montefiore Cough Center in Bronx, New York. One of the recurring themes of the conference was the recognition that although ideally, cough therapy is specific to the origin of the cough, often chronic cough is idiopathic. Over-the-counter cough remedies have not been well studied.

A few interesting articles were discussed that looked at the effectiveness of inert ingredients in cough syrups (menthol and sucrose). For example, a small study of patients with chronic cough treated with nebulized menthol before a capsaicin inhalational challenge showed a beneficial effect of menthol.[2] Although this is encouraging for cough sufferers, it raises some disturbing questions about the rationale for mentholated cigarettes.

Paul Wise, PhD, a sensory psychologist at the Monell Chemical Senses Center in Philadelphia, Pennsylvania, said that the effect in this study was probably due to nasal inhalation of menthol. Dr. Wise said a similar study he authored with colleagues found that simply breathing air that has been mentholated is sufficient as a cough therapy, and that rinsing with sucrose, another ingredient common to cough syrup, is also partially effective.[3]

Dr. Dicpinigaitis, who is also Professor of Clinical Medicine at Albert Einstein College of Medicine, Bronx, New York, presented a case of a refractory cough patient and discussed the approach he takes to chronic cough per the American College of Chest Physicians Guidelines.[4] He said that if there is no obvious cause, then he starts with a first-generation sedating antihistamine.

The rationale for this has to do with the cough receptor TRPV1, which is a muscarinic receptor. Only the older antihistamines (such as chlorpheniramine) penetrate the blood/brain barrier to act centrally, hence also causing sedation. Newer H1-antihistamines (eg, cetirizine, fexofenadine, loratadine, and desloratadine) do not have this effect.

If a sedating antihistamine is not effective, then Dr. Dicpinigaitis proceeds to a trial of oral prednisone (40 mg for 5 days, then 20 mg for another 5 days). He prefers prednisone to inhaled steroids owing to both speed of symptom relief and efficacy. His reasoning is that it takes up to 8 weeks to see a response in cough-variant asthma and that the airways are so sensitive in some patients that the steroid propellant itself may trigger the cough.

If the patient is still coughing, then Dr. Dicpinigaitis treats for acid reflux with twice-daily proton pump inhibitor therapy. If there is a residual cough, he may add a prokinetic agent (metoclopramide).

Alan Goldsobel , MD, an allergist and clinical professor at the University of California, San Francisco, suggested using dexbrompheniramine as an alternative to chlorpheniramine and said that he often combined it with multiple nasal sprays (steroid, antihistamine, and anticholinergic). Kenneth Altman, a laryngologist and associate professor of Otolaryngology at Mount Sinai School of Medicine, discussed evaluating patients for laryngeal sensory neuropathy but stated that this was a diagnosis of exclusion.

Thomas Murry, PhD, Professor of Speech-Language Pathology in the Department of Otorlaryngology at Weill Medical College of Cornell University, New York, New York, said he treats cough and dyspnea of laryngeal origin with limited speech therapy and reports excellent results in just a few sessions. Dr. Murry stated that 80% of patients with chronic cough are found to have paradoxical vocal fold motion, but this may simply represent an adaptive response to protect the airway from further injury.

The speakers seemed in agreement that chronic cough may be a self-perpetuating process. For example, coughing increases transdiaphragmatic pressure, leading to reflux and cough. Research presented at the 2013 American Cough Conference will be published in the journal Lung at a later date.

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