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.