A CLINICAL-STUDY TO EVALUATE THE EFFICACY OF THE ANTIHISTAMINE DOXYLAMINE SUCCINATE IN THE RELIEF OF RUNNY NOS AND SNEEZING ASSOCIATED WITHUPPER RESPIRATORY-TRACT INFECTION

Antihistamines are widely used in common cold medications, although th e role of histamine in the development of common cold symptoms is uncl ear and the use of antihistamines for the treatment of common cold is controversial. It is clear that antihistamines do not offer a cure for common cold but they may alleviate symptoms of sneezing and runny nos e. The present study was designed to investigate the efficacy of an an tihistamine, doxylamine, on the symptoms of runny nose and sneezing as sociated with common cold. We conducted a randomized double-blind stud y in cold sufferers. One thousand and one volunteers with cold symptom s were screened in four centres (UK, Denmark, Belgium, Germany) and 68 8 satisfied the entry criteria of the study. The main reasons for excl uding subjects were a low nasal secretion weight (secretion weight < 0 .2 g, 72%) and a low subjective rhinorrhoea score (24%). Volunteers we re randomized to receive either doxylamine succinate 7.5 mg by mouth f our times a day up to nine doses (n = 345) or placebo (n = 343). The p rincipal measurements were prospectively defined as runny nose and sne ezing symptom scores. Data were analysed on an intention-to-treat basi s, using Cochran-Mantel-Haenszel statistics controlling for baseline s ymptom scores. A between-group comparison showed that doxylamine-treat ed volunteers benefited from a significantly greater reduction in runn y nose scores (P < 0.01) and sneezing scores (P < 0.001), than those v olunteers in the placebo group. Doxylamine therapy was well tolerated; the incidence of unexpected side-effects was comparable with placebo. Of the expected side-effects, 13.3% of doxylamine-treated patients re ported drowsiness. The incidence of sedative effects was lower than ha s been reported for other commonly used first-generation antihistamine s.