Circadian rhythms : chronotherapeutic study of non-sedating antihistamines in treating allergic rhinitis

الملخص EN

Objectives: the first aim of this study is to determine if there is circadian rhythm variation in persistent allergic rhinitis symptoms.

The second aim is to evaluate the role of morning vs.

evening non-sedating antihistamine therapy in achieving the improvement of these symptoms. Patients and methods: One hundred patient suffering from allergic rhinitis symptoms were included in this study.

A questionnaire regarding allergic rhinitis symptom was filled for each patient.

Five symptoms (nasal itching, runny nose, nasal blockage, sneezing and eye symptomsj were graded from 0 to 3 (no, mild, moderate and sever respectively) with total symptom score equals 15.

This questionnaire was filled before therapy.

The patients were randomly divided into two groups, one group received non-sedating antihistamine once daily (cetirizine hydrochloride 10 mg or desloratidine 5 mg) at morning (AM-group) and the other one received the same antihistamine at evening (PM-group).

The same questionnaire was filled again after 2 weeks for each patient. Results: Both Binomial Method and Kolmogorov-Smirnov Test (non-parametric tests) indicate that there was a significant difference between the total scores of symptoms at morning "AM" and night "PM".

P-Value of any of the two tests was less than 0.05.

Using Spearman Rank Correlation, any symptom tends to lower its intensity during night.

After treatment, using Kolmogorov-Smirnov test, TSS in PM-group is very significantly lower than that of AM-group.

The adverse events were comparable in both groups and also comparable for cetirizine and desloratidine.

The commonest side effects were gastro-intestinal upset (nausea and abdominal discomfort) in 13 patients (13%) and headache in 11 patients (11%).

Conclusion: The present study confirmed the morning versus evening variation of allergic rhinitis symptoms.

The symptoms were more worse in the early morning.

Giving antihistamine medication at night has a better therapeutic outcome in most of the patients.

However, the timing of treatment must be individualized to each patient according to his own symptoms' circadian rhythm.

Key words: Circadian rhythm, allergic rhinitis, antihistamine.