To Evaluate Adenosine Monophosphate and Allergen Challenge in Allergic Rhinitis

A Placebo Controlled Trial to Evaluate The Effects of Levocetirizine on Nasal Allergen Challenge And Adenosine Monophosphate Challenge In Patients With Intermittent and Persistent Allergic Rhinitis

Allergic rhinitis is a common condition characterize by inflammation of the upper airways. Third generation antihistamines have been demonstrated effective in the treatment of this condition. Allergen challenge can be use to assess the effects of drugs in allergic rhinitis, adenosine monophosphate may also be used as a means to investigate these effects but as yet its effects have yet to be compared to allergen challenge. We intend to compare the effects of levocetirizine at a single dose of 5mg on allergen and AMP challenge compared to placebo in a double blind cross-over study. The study will include 20 patients with allergic rhinitis. Each patient will have allergen and AMP challenge on placebo and active treatment. The primary outcome variable will be the change in concentration of AMP/Allergen required to produce a 20% drop in nasal flow as manifest by peak nasal inspiratory flow. A 1 doubling dose change in concentration of challenge medium to cause a 20% drop in nasal flow will be deemed significant. We will also measure time to recovery after both challenges. AMP challenge is a safe alternative to allergen challenge and does not have the risk of anaphylaxis.

Inclusion Criteria:

• Male or female 16-75
• Patients with persistent rhinitis must be skin prick positive to house dust mite with perennial symptoms
• Patients with seasonal rhinitis should be skin prick positive to grass/tree pollen with seasonal symptoms
• Concomitant asthma is permitted in those with rhinitis if FEV1 >60%
• No recent exacerbations of asthma or chest infections if asthmatic
• Able to perform all of the techniques necessary to carry out challenge testing
• Must be compliant to study medication
• Must give informed consent

Exclusion Criteria:

• Male or female outwith the above age range
• Negative skin prick testing
• Patients with concomitant asthma with FEV1 less than 60% predicted
• Patients with asthma with recent chest infection or exacerbation
• Pregnant females, those at risk of becoming pregnant or breast feeding. Females must be on adequate contraception for the whole study period