A double-masked, placebo-controlled polysomnographic study of the antitussive effects of helicidine

Abstract

Background: Helicidine is a nonnarcotic antitussive medication consisting of several mucoglycoproteins extracted from the mucus of the snail Helix pomatia. Helicidine has been used for > 40 years in France as a cough medicine. Objective: The purpose of this double-masked polysomnographic study was to compare the antitussive effect of helicidine 10% syrup with that of an identical placebo syrup. Methods: Patients with stabilized chronic obstructive lung disease had to have ≥20 cough episodes per night or 3 per sleeping hour for 2 consecutive nights to be eligible; helicidine or placebo syrup was then administered for 3 days (two 15-mL doses 3 times daily), and efficacy variables were recorded during the last 2 nights. Compliance was assessed by measuring the syrup left in the bottles (one 125-mL bottle per day). Primary efficacy end points included the frequency and relative duration of cough episodes during the sleeping period. Secondary efficacy end points included the number of microawakenings per night, modified Spiegel score (1 item regarding nocturnal cough was added), and scores from patient and investigator Clinical Global Impression assessments. Tertiary (exploratory only) efficacy end points included sleep efficacy and frequency and relative duration of cough during the falling asleep and awakening periods. Results: Fifteen men and 15 women were included in the study (15 in the helicidine group and 15 in the placebo group). The frequency and relative duration of cough during the sleeping and awakening period were significantly less ( P < 0.05) with the use of helicidine versus placebo, whereas no difference between placebo and helicidine could be detected for the secondary and the 3 other tertiary efficacy end points. Helicidine was well tolerated; 1 minor adverse effect (diurnal drowsiness) occurred in each group. Compliance was considered satisfactory in 19 of 30 patients. Conclusions: Helicidine was effective as an antitussive agent in this sample of patients, reducing both the number and the duration of cough episodes per hour during the sleeping period. This agent can thus be recommended for the treatment of nonproductive cough, especially in patients in whom opioid or antihistaminic antitussive agents are contraindicated.