Clinical Trial of Efficacy and Safety of Levopront® 30 mg/5 ml in Patients With Dry Cough

Inclusion Criteria: Subjects should meet the following inclusion criteria to be included into this clinical trial: 1. Signed Informed Consent Form 2. Male or female aged from 18 to 65 (inclusive) 3. Dry non-productive cough as a symptom of acute upper respiratory infection (IDC codes J00-J06) 4. Daytime cough symptom score ≥ 3 points according to the "Six-point daytime and nighttime cough assessment scale" 5. Pre-bronchodilator FEV1 ≥ 70% of the predicted values, post-bronchodilator FEV1 increase of ≤ 12% or ≤ 200 ml compared to the baseline, FEV1/FVC (Tiffeneau index) ≥ 0.7 6. Patient's consent to follow the protocol procedures, including the completion of the patient's diary 7. Patient's consent to use the adequate contraception methods throughout the study period. The adequate birth control methods are as follows: * Oral or transdermal contraceptives * Condoms or diaphragms (barrier method) with spermicide * Intrauterine contraceptive devices Exclusion Criteria: Subjects with any of the following conditions will be excluded from the study: 1. Hypersensitivity or individual contraindications to Levodropropizine, Prenoxdiazine or additives of the study drug 2. Hereditary fructose intolerance, glucose-lactose malabsorption, lactase deficiency, sucrose-isomaltose deficiency 3. Tuberculosis, bronchial asthma, malignant tumors of lungs or bronchi, COPD, severe respiratory failure (cyanosis, need for respiratory support) or other lung pathology at screening or in history 4. Inhalation anesthesia within 3 months before screening 5. Smoking history of more than 10 pack-years 6. Previous use of cough medicines, ACE inhibitors or amiodarone within 30 days before screening 7. Contraindications or inability to perform spirometry 8. Necessity (in the Investigator's opinion) of prescribing mucolytic agents, expectorants, antibiotics or other medications prohibited by the protocol during the study 9. Excessive mucous excretion which (in the Investigator's opinion) could be a contraindication to prescribing anti-cough medicines; decreased mucociliary function (Kartagener's syndrome, ciliary dyskinesia) 10. Malignant tumors in the past 5 years (except for the basal cell carcinoma) 11. Serious cardiovascular disease at the moment or within 12 months prior to screening, including: Chronic heart failure class III or IV (according to the classification of the New York Heart Association), severe arrhythmias requiring treatment with antiarrhythmic drugs class Ia, Ib, Ic or III, unstable angina, myocardial infarction, heart surgery and coronary arteries, serious valvular heart disease, transient ischemic attack or stroke, uncontrolled hypertension with systolic blood pressure \> 180 mmHg and diastolic blood pressure \> 110 mmHg, pulmonary embolism or deep vein thrombosis 12. Gastric or duodenal ulcers, gastroesophageal reflux disease within a period of 12 months before screening 13. Systemic autoimmune disorders and connective tissue diseases that require (currently or previously) administration of systemic glucocorticosteroids, cytostatic medications or penicillamine 14. Signs of intensive non-controlled concurrent disease, including disorders of the nervous system, endocrine system, kidneys, liver or gastrointestinal tract, which (in the Investigator's opinion) could prevent the patient's participation in the study 15. History of alcohol or drug abuse at screening or in the past, which results in the inability of the patient to participate in the study at the Investigator's discretion 16. Taking part in another clinical trial or use of study drug within 30 days before screening 17. Pregnant or breast-feeding women or women planning pregnancy during the clinical trial; women of childbearing potential (including not sterilized operatively and in postmenopausal period of less than 2 years), not using appropriate methods of contraception 18. Inability to read or write; unwillingness to understand and follow the procedures of the study protocol; violation of the drug administration regimen or procedure execution that, at the discretion of the Investigator, can impact he results of the study or safety of the patient and interfere his further participation in the study; any other concomitant medical or serious mental conditions that make the patient unsuitable for participation in the clinical study, limit the validity of receiving an informed consent or may affect the patient's ability to participate in the study.