Assessing a new treatment for chronic cough in adults

Inclusion Criteria:

* Refractory or unexplained chronic cough for ≥ 12 months.
* Women of childbearing potential agree to follow the protocol specified contraceptive - guidance during the study.
* Males who are not vasectomized must agree to use the contraceptive methods defined in the protocol.
* Able to provide Informed Consent.

Exclusion Criteria:

* Previous exposure to taplucainium (formerly NTX-1175) or known allergy or hypersensitivity to taplucainium, its excipients/metabolites, or related compounds.
* Participants who are currently participating in another drug or device clinical study
* Participants who have participated in an Acute or Chronic Cough investigational study within 60 days before the start of the Screening.
* Current diagnosis of chronic obstructive pulmonary disease, bronchiectasis, unexplained pulmonary fibrosis, hemoptysis, bronchial asthma, or other pulmonary disease.
* Respiratory tract infection within 4 weeks of Screening or during screening period.
* Any female who is pregnant or lactating or wishing to become pregnant.
* Donation of \> 1 Unit (450 milliliter or more) of blood within 60 days prior to the first dosing.
* Alcohol or drug use disorder within the past 2 years.
* Current smoker/vaper or individuals who have given up smoking within the past 6 months of screening, and/or those with \>20 pack-year smoking history.
* Current opiate/opioid use or medical history of opiate/opioid use disorder.
* History of concurrent malignancy or recurrence of malignancy in the last 2 years.
* Body Mass Index of ≥40 kg/m2.
* Positive results for human immunodeficiency virus, hepatitis B, or hepatitis C virus.
* Unable to refrain from the use of medications and treatments that can impact cough during the study.
* Have clinically significant history or evidence of poorly controlled cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, neurological, immunological, or psychiatric disorder(s).