Intranasal antihistamines in the treatment of idiopathic non-allergic rhinitis: a systematic review and meta-analysis.

Background: Idiopathic rhinitis (IR), previously known as vasomotor rhinitis (VMR), is the most common type of non-allergic rhinitis (NAR) which affects around 100 million people worldwide. The treatment of patients with IR is not standardized. Intranasal antihistamines (INAH) are potent drugs in the treatment of allergic rhinitis but are frequently prescribed in the treatment of IR. This systematic review of the literature and meta-analysis aims to assess the effects of INAH on IR.

Methodology: A comprehensive review of the literature was conducted on Medline, Embase and Cochrane library. Randomized, controlled trials and non-randomized comparative parallel group trials comparing INAH to placebo or different INAHs were included. The primary outcome was the change in disease specific quality of life questionnaires, total nasal symptom score (TNSS). The secondary outcomes were other reported nasal symptom scores, individual symptom scores and adverse events.

Results: Six trials out of 987 assessing a total of 675 participants were deemed relevant for inclusion. Compared to placebo, INAH decreased total nasal symptom scores. One study also reported reduction of symptoms recorded on a visual analogue scale. There was no difference between the INAHs in terms of efficacy. Bitter taste sensation was the most frequently reported adverse event.

Conclusions: INAHs seem to have benefit over placebo on nasal symptoms improvement in the treatment of NAR. No superiority between INAHs was identified.