Refractory Chronic Cough (RCC): Clinical Reference

This interactive clinical reference—part of CHEST's Bridging Specialties^®: Timely Diagnosis and Treatment for Refractory Chronic Cough program—guides clinicians through a structured, guideline-directed approach to RCC across four key domains. Embedded clinical guidance is provided at each step.

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Epidemiology and Burden of RCC | CHEST Algorithm: Diagnostic Pathway | Current Treatment Options | Novel and Emerging Treatments

Epidemiology and
Burden of RCC

CHEST Algorithm:
Diagnostic Pathway

Current
Treatment Options

Novel and
Emerging Treatments

Epidemiology and burden of refractory chronic cough

Affecting ~16.8% of patients with chronic cough, RCC predominantly impacts women (2-3× prevalence) with a median diagnostic delay of 24 months. RCC can be debilitating and requires timely recognition and structured, multidisciplinary management.

GLOBAL PREVALENCE

~10%

of adults affected by chronic cough globally

SEX DISTRIBUTION

~67%

of patients with RCC are female, linked to more sensitive cough reflex

MEDIAN AGE

59 yrs

at presentation to specialist cough clinic

SEX DISPARITY

2-3 times

more common in women than men

DIAGNOSTIC DELAY

24 months

median time to specialist diagnosis

EMOTIONAL BURDEN

~70%

of patients express frustration at the persistence of their condition and the lack of effective treatments

CHEST algorithm and diagnostic pathway

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Adapted from: Irwin RS, et all. Chest. 2018;153(1):196–209; Morice AH, et al. Eur Respir J. 2020;55(1):1901136.

Rule Out Before RCC Diagnosis

Condition	Clinical Clues	Initial Management
UACS	Post-nasal drip, throat clearing	Antihistamine + nasal steroid (6–8 weeks)
Asthma/CVA	Wheeze, broncodilator response	LCS ± LABA ≥ 8 weeks
NAEB	Sputum eos ≥ 3%	ICS 8–12 weeks
GERD	Heartburn, regurgitation	PPI BID 8–12 weeks

Before Diagnosing RCC, Confirm:

Adequate dose
Adequate duration
Adherence confirmed

Common Causes Evaluation Guide

A structured approach to chronic cough evaluation supports accurate diagnosis by ensuring common etiologies are identified and treated before confirming RCC.

Rule out UACS, asthma/CVA, NAEB, and GERD/LPRD
Initiate guideline-aligned treatment trials
Reassess response before advancing diagnosis
Confirm adequate dose, duration, and adherence prior to diagnosing RCC

Rule Out Before RCC Diagnosis

Condition	Clinical Clues	Initial Management
UACS	Post-nasal drip, throat clearing	Antihistamine + nasal steroid (6–8 weeks)
Asthma/CVA	Wheeze, broncodilator response	LCS ± LABA ≥ 8 weeks
NAEB	Sputum eos ≥ 3%	ICS 8–12 weeks
GERD/LPRD	Heartburn, regurgitation	PPI BID 8–12 weeks

Before Diagnosing RCC, Confirm:

Adequate dose
Adequate duration
Adherence confirmed

Current treatment options

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Ordered by recommendation priority

Treatment	Key agents	Clinical notes
First-Line Nonpharmacologic Therapy	Speech-language pathology Cough suppression therapy	Physiotherapy cough suppression: education, controlled breathing, laryngeal hygiene 30%–50% reduction in objective cough frequency in randomized controlled trials (RCTs); durable effect at 12 months and effective via telehealth Should be offered to ALL eligible patients with RCC
Second-Line Off-Label Neuromodulators	Gabapentin Pregabalin Amitriptyline (selected)	Most commonly used off-label options for RCC Gabapentin/pregabalin target central sensitization via α2δ subunits Amitriptyline: low-dose tricyclic with evidence in chronic cough Central nervous system side effects (dizziness, sedation) limit tolerability in some patients
Adjunctive Symptomatic Antitussives	Benzonatate Nonopioid antitussives	Used for short-term symptomatic relief; no proven disease-modifying effect in RCC May be appropriate while awaiting specialist referral
Select Cases Opioids	Low-dose slow-release morphine (5–10 mg SR)	RCT evidence in refractory cough; reserve for patients who have failed other treatments Risks: constipation, sedation, dependence potential; not a first-line or second-line recommendation

Novel and emerging treatments

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P2X3 antagonists and opioid modulators in active development

P2X3 antagonists and opioid modulators in active development, including agent, mechanism and status, and key trial data.
Agent	Mechanism and status	Key trial data
★ Most Advanced Camlipixant Phase 3 Enrolling	Selective P2X3 antagonist > 1,500× selectivity over P2X2/3	34.4% reduction in 24-h cough frequency (SOOTHE, n = 249) 6.5% dysgeusia rate at 50 mg bid Phase 3 CALM-1 (52-wk) & CALM-2 (24-wk) actively enrolling; ~825 patients each Topline results expected 2025-2026; regulatory submissions anticipated thereafter
EU and Japan Approved Gefapixant Phase 3 Complete	P2X3/P2X2/3 antagonist Nonselective; blocks adenosine triphosphate–mediated cough drive on vagal C-fibers	18.5% reduction in 24-h cough frequency vs placebo (COUGH-1/2, n = 2,044) ~69% dysgeusia rate (off-target P2X2/3 blockade on lingual neurons) Approved in EU and Japan; FDA Complete Response Letter 2023; not US-approved
Nalbuphine ER Phase 2b Planned	Kappa/mu-opioid modulator (KAMA) Dual kappa agonist and mu antagonist; central and peripheral mechanism	67% reduction in cough frequency (RIVER, N = 66) 57% placebo-adjusted reduction (P < .0001) CORAL (idiopathic pulmonary fibrosis cough): positive phase 2b results published in JAMA, January 2026 Phase 2b RCC trial planned Q2 2026; phase 3 program in design

References

Bali RK. Epidemiology and burden of refractory chronic cough. J Thorac Dis. 2024; data on file.
Bali V, Schelfhout J, Sher MR, et al. Patient-reported experiences with refractory or unexplained chronic cough: a qualitative analysis. Ther Adv Respir Dis. 2024;18:17534666241236025.
CHEST Analytics. Time to RCC diagnosis: from initial specialist referral to confirmed diagnosis. 2025; data on file.
Chung KF, McGarvey L, Song WJ, et al. Cough hypersensitivity and chronic cough. Nat Rev Dis Primers. 2022;8(1):45.
Gibson PG, Wang G, McGarvey L, et al. Treatment of unexplained chronic cough: CHEST guideline and expert panel report. Chest. 2016;149(1):27-44.
Irwin RS, French CL, Chang AB, Altman KW; CHEST Expert Cough Panel. Classification of cough as a symptom in adults and management algorithms: CHEST guideline and expert panel report. Chest. 2018;153(1):196-209.
McGarvey LP, Birring SS, Morice AH, et al. Efficacy and safety of gefapixant, a P2X₃ receptor antagonist, in refractory chronic cough and unexplained chronic cough (COUGH-1 and COUGH-2): results from two double-blind, randomised, parallel-group, placebo-controlled, phase 3 trials. Lancet. 2022;399(10328):909-923.
Morice AH, Millqvist E, Bieksiene K, et al. ERS guidelines on the diagnosis and treatment of chronic cough in adults and children. Eur Respir J. 2020;55(1):1901136.
Ryan NM, Birring SS, Gibson PG. Gabapentin for refractory chronic cough: a randomised, double-blind, placebo-controlled trial. Lancet. 2012;380(9853):1583-1589.
Smith JA, Birring SS, Blaiss MS, et al. Camlipixant in refractory chronic cough: a phase 2b, randomized, placebo-controlled trial (SOOTHE). Am J Respir Crit Care Med. 2025;211(6):1038-1048.
Song WJ, Chang YS, Faruqi S, et al. The global epidemiology of chronic cough in adults: a systematic review and meta-analysis. Eur Respir J. 2015;45(5):1479-1481.
Stolz D, Smith JA, Beadnell M. The significance and psychosocial burden of refractory chronic cough. EMJ Respir. 2025;13[Suppl 1]:2-11.
Sykes DL, Morice AH. Cough hypersensitivity syndrome — a review of the current evidence. Pharmacol Ther. 2022;237:108166.
Trevi Therapeutics. Positive topline results from the Phase 2a RIVER trial of nalbuphine ER in patients with refractory chronic cough [press release]. March 10, 2025. ClinicalTrials.gov: NCT05962151
van Boemmel-Wegmann S, Altman KW, Herrera R, et al. Characteristics of adults with potential refractory chronic cough identified using an algorithm designed for administrative claims databases. Sci Prog. 2024;107(1):368504241238080.
Vertigan AE, Theodoros DG, Gibson PG, Winkworth AL. Efficacy of speech pathology management for chronic cough: a randomised, single blind, placebo controlled trial. Thorax. 2006;61(12):1065-1069.