Tecastemizole ['Soltara'], a novel antihistamine, has rapid and prolonged activity in the treatment of seasonal allergic rhinitis, according to results from three phase III studies presented at the 58th Annual Meeting of the American Academy of Allergy, Asthma and Immunology (AAAAI) [New York, US; March 2002]. In one study, single doses of tecastemizole 30mg provided rapid and sustained relief of symptoms, starting as early as 20 minutes after administration. Two separate studies showed that once-daily administration of tecastemizole for two weeks was effective in reducing total, nasal and non-nasal symptoms from the first day of treatment. Tecastemizole was well tolerated in all three studies, with the incidences of adverse events being comparable to the placebo groups, and no evidence of QTc interval prolongation.