Controlled clinical study of the efficacy of loratadine in Nigerian patients with allergic rhinitis.

An observer blind clinical study was carried out among 64 Nigerian patients with allergic rhinitis to assess the efficacy and tolerance of loratadine a new generation H1 antihistamine. Patients were allotted randomly to receive treatment for 1 week with either loratadine + Vit. C (group A), chlorpheniramine + Vit. C (group B), or Vit. C alone (group C). Assessment was by subjective symptom scoring of three nasal symptoms namely; sneezing, rhinorrhoea and nasal blockage. Difference between pre treatment and post treatment mean symptom scores was used as degree of improvement for statistical analysis and this formed the primary efficacy parameter. Adverse effects namely; anticholinergic effects, gastrointestinal effects and drowsiness were assessed following treatment. The results showed that loratadine was significantly better than Vit. C. alone (P = 0.0002) and chlorpheniramine was also significantly better than Vit. C. alone (P = 0.039). However, loratadine was significantly better than chlorpheniramine P = 0.046. Drowsiness was noted in 19.2% of patients on loratadine compared with 57.1% of patients on chlorpheniramine. lt is concluded that though both loratadine and chlorpheniramine were effective in the relief of symptoms of allergic rhinitis in Nigerian patients, loratadine was significantly more effective with minimal sedating effect.