A Randomized Dose‑Ranging Study of Nalbuphine Hydrochloride Extended‑Release Tablets in Adults with Refractory Chronic Cough

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What is this study about?

The study examines individuals with Refractory Chronic Cough, a cough that continues despite standard treatments. The medication being tested is Nalbuphine ER, an oral tablet designed to release the drug slowly over time (extended‑release). A matching placebo tablet is also used. The purpose of the study is to evaluate the effect of the medication on the number of coughs per hour after six weeks.

Participants will be randomly assigned to receive either a low dose (54 mg), a higher dose (108 mg) of the study drug, or the placebo, and will take the tablet once daily for several weeks. The trial is double‑blind, meaning neither the participants nor the study staff know which tablet is being taken. Cough frequency will be recorded with a small device that counts coughs over a 24‑hour period at the start of the study and again at scheduled visits, including the main assessment at week six. Safety checks and routine visits will occur throughout the study period.

1 enrollment and randomization

after you agree to join the study, you are assigned a random treatment group. the assignment is done by a computer so that neither you nor the study staff knows which group you are in.

the possible groups are nalbuphine er 54 mg, nalbuphine er 108 mg, or a matching placebo tablet.

2 receiving the study medication

you receive a supply of film‑coated tablets that are taken by mouth. each tablet contains either 54 mg or 108 mg of nalbuphine hydrochloride, or no active medicine (placebo).

the tablets are designed as extended‑release formulations, meaning the medicine is released slowly over time after you swallow the tablet.

3 daily dosing

you take one tablet each day, at the same time each day, for a total of six weeks.

the tablet is swallowed whole with a glass of water. you do not need to crush or chew the tablet.

if you are assigned the placebo, you follow the same schedule using the matching tablet.

4 cough monitoring

throughout the study you wear a small cough monitor that records the number of coughs you make over a 24‑hour period.

the monitor is used at the start of the study (baseline) and again at scheduled visits, especially at week 6.

5 week 6 clinic visit

after six weeks of daily dosing, you attend a clinic visit.

the study team compares the cough count recorded by the monitor with the baseline count to see how your cough frequency has changed.

they also check for any side effects or safety concerns.

6 end of treatment and final assessment

following the week‑6 visit, the study medication is stopped.

a final assessment may be performed to record any remaining symptoms or side effects.

after this point you are no longer required to take study tablets or wear the cough monitor.

Who Can Join the Study?

Be a man or woman who is at least 18 years old when you sign the study paperwork.
Sign a written informed consent form that also allows the study team to use your health information that is normally kept private.
Have a diagnosis of Refractory Chronic Cough (RCC) that meets the expert guidelines, meaning either the cough did not get better enough after treating any known cause, or the cough remains unexplained even after doctors have done appropriate tests and treatment attempts.
Have a cough that has lasted for at least one year before the screening visit.
Have had a chest CT scan (a detailed X‑ray) or a regular chest X‑ray done within the past 24 months (and after the cough started) or be willing to have one done during screening, and the images must not show any serious problem that could explain the cough, according to the study doctor.

Who Cannot Join the Study?

Having a clinical diagnosis of sleep apnea or using a Continuous Positive Airway Pressure (CPAP) machine, which helps keep the airway open while sleeping.
Having an upper or lower respiratory tract infection (infection of the nose, throat, or lungs) or any change in lung health (pulmonary status) in the 4 weeks before screening, or during the screening or placebo run‑in periods.
Having a history of serious breathing disorders such as bronchiectasis (damage to the airways), chronic obstructive pulmonary disease (COPD) (a long‑term breathing problem), idiopathic pulmonary fibrosis (IPF) (scarring of lung tissue), or other significant respiratory conditions that could affect coughing.
Having uncontrolled asthma, defined as either:
- at least one clinically significant exacerbation (asthma flare‑up) in the past 6 months, or
- two or more clinically significant exacerbations in the past 12 months, where a significant exacerbation means needing treatment with systemic corticosteroids (strong steroids taken by mouth or injection).

Where you can join this trial?

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Other Sites

Site Name	City	Country
Uniwersytecki Szpital Kliniczny W Poznaniu	Poznan	Poland
Samodzielny Publiczny Wojewodzki Szpital Zespolony W Szczecinie	Szczecin	Poland
Sylwia Matusiewicz MATMEDICA	Wroclaw	Poland
Uirdlpoaoccva Swwtfju Ksbydxspf Nh 1 Is Ntikrwkf Bqkzddrswho Uqyuzmlaqksp Mfddnfhwmu W Lohzn Smooi	Lodz	Poland
Nwlbjvje Immmquwre Or Tnsrrhuwbxkp Aob Lxfc Dqeqtkww	Warsaw	Poland
Cnsxaegoq Dytwhjq Nvzxa Stn ku	Bialystok	Poland
Mefozuavgxb Csmdvos Lajfljyn Cpfzpq Pkyw I Gyiasbie	Otwock	Poland
Ojptxikktnnh Cryynjz Mmhavbtx Aqlb Oleavapuarxs Kqbkxwnyb Cluutn swpj	Ostrowiec Swietokrzyski	Poland

Trial status

Country	Status	Recruitment Start
Poland	Not yet recruiting	19.10.2026

Trial locations

Investigated Drugs:

Nalbuphine Hydrochloride

Nalbuphine ER is an oral extended‑release tablet that contains nalbuphine, a medication that works on the body’s opioid receptors to help calm the cough reflex. In this study participants took the tablet once daily to see if it could lower the number of coughs they have over a 24‑hour period. The trial tested different strengths of the same tablet to find the dose that works best while staying safe.

Investigated Diseases:

Cough

Refractory chronic cough – A persistent cough that lasts for at least eight weeks and does not improve with usual treatments. It is often triggered by irritants, infections, or underlying airway sensitivity. Over time, the cough may become more frequent and intense, interfering with daily activities. The condition can lead to throat irritation, hoarseness, and sleep disturbance. It may gradually worsen if the underlying cause remains untreated.

Trial ID:

2026-526087-20-00

Protocol code:

NAL04-202

Trial Phase:

Therapeutic exploratory (Phase II)

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A Randomized Dose‑Ranging Study of Nalbuphine Hydrochloride Extended‑Release Tablets in Adults with Refractory Chronic Cough

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?