The goal of this monocentric double blinded cross over trial is to evaluate safety and tolerability of inhaled furosemide in patients with pulmonary diseases and dyspnea.

The main question[s] it aims to answer are:

• is inhaled furosemide safe and well tolerated?
• is inhaled furosemide capable of dyspnea suppression and is there any additive effect of levodropropizine

Participants will be given:

• inhaled furosemide or placebo in double blinded cross over manner. Dyspnea severity and vital functions will be measured, adverse reactions monitored
• all participants will receive levodropropizine open label. Dyspnea severity and vital functions will be measured, adverse reactions monitored

102 subjects from the pool of patients hospitalized in our pulmonary clinics will be randomized in 1:1 ratio to 2 arms in double blinded manner. Subjects in both arms will inhale first vial of study medication - furosemide 40 mg or placebo (saline). Dyspnea severity and vital functions will be measured, adverse reactions will be monitored. After an hour the subjects will inhale the second vial of study medication followed by the same procedure as earlier. Neither subjects, nor investigators will know which vial contains furosemide and which contains placebo. At last all subjects will receive levodropropizine open label and the dyspnea severity, vital signs and adverse reaction will be monitored for another hour. The measured values will be statistically evaluated a results published.

Inclusion Criteria:

• ability to understand and sing written consent
• ability to use visual analogue (VAS) and Borg dyspnea scale
• presence of lung disease (asthma, chronic obstructive pulmonary disease, interstitial pulmonary disease, tumour affecting lungs, Coronavirus Disease 2019 (COVID19), drug induced dyspnea, lung infection)
• dyspnea at least 50 points in VAS and at least 5 point in Borg dyspnea scale
• women of childbearing age consent ot avoid sexual intercourse during the study participation

Exclusion Criteria:

• hypersensitivity to furosemide, levodropropizine or any additives in studied drugs
• mucociliary disorder (kartegener syndrome, ciliary dyskinesis)
• severe liver disease - cirrhosis Child Pugh B or C
• renal failure, creatinine clearance less than 35 ml/min
• unstable patient requiring frequent treatment changes
• patients with continual intravenous medication requiring modification of their therapy more often than ever 4 hours
• unability to participate in all study procedures
• pregnancy, breast feeding
• participation in other clinical trial with administration of study drug in last 28 days or 5 half times of studied drug (the longer period is taken into account) before screening

The subjects and investigators as well as care provider will not know the order of the studied substances given to subjects.