Pharmacology Update

Azelastine Hcl: A New Nasal Spray

By William T. Elliott, MD, and James Chan, PharmD, PhD

A new nasal spray is joining the $1.5 billion per year allergy medication market. Azelastine (Astelin, Wallace) is the first antihistamine nasal spray to be approved by the FDA. The preparation is a histamine-1 receptor antagonist formulated as a metered spray solution. It is approved for the treatment of symptoms of seasonal allergic rhinitis such as rhinorrhea, sneezing, and nasal pruritus in adults and children 12 years and older.

Potential Advantages

Azelastine is FDA approved for symptomatic relief of nasal symptoms, but studies suggest that non-nasal symptoms are also improved and may be comparable with symptom relief achieved with chlorpheniramine. Chlorpheniramine sustained release tablets (12 mg bid) have been used as a positive control in comparative studies, but the studies did not have sufficient statistical power to detect a difference between chlorpheniramine and azelastine.1-3 Relief of non-nasal symptoms may be related to systemic bioavailability of 40% after intranasal administration.4 Rebound or tachyphylaxis, seen with decongestants, were not reported for azelastine. There is no evidence of any significant effect on QTc intervals when azelastine is used with ketoconazole or erythromycin.4

Potential Disadvantages

The most common side effects of azelastine include bitter taste (19.7%), somnolence (11.5%), and nasal burning (4.1%).4 The concomitant use of alcohol or other CNS depressants may enhance the potential for somnolence. In a comparative trial, beclomethasone and azelastine were both effective in relieving nasal symptoms, but azelastine did not demonstrate antiinflammatory action as assessed by a reduction in eosinophils recovered in the nasal lavage.5

Dosing Information

Azelastine is dosed at 2 puffs bid. It is supplied as a nasal spray, 137 mcg per spray.

Comments

Azelastine is a histamine-1 receptor antagonist that relieves nasal and perhaps non-nasal symptoms. The onset of action is about two hours, peak action is five hours and duration about 12 hours.3,6 Comparative data assessed by symptom scores suggest that azelastine is comparable to traditional antihistamines such as chlorpheniramine as well as the newer nonsedating agents such as terfenadine and loratadine.1-3,7,8

Clinical Implications

Azelastine nasal spray is another antiallergy medication in an already crowded market. It may offer some advantages over oral medications and the antiinflammatory sprays or decongestant sprays for selected patients. It is, however, very expensive, at $1.42 per day.

References

1. Storm WW, et al. ENT J 1994;73:382-394.

2. Ratnor PH, et al. J Allergy Clin Immunol 1996;94: 818-825.

3. Melzer EO, et al. Ann Allergy 1994;72:354-359.

4. Astelin Product Information. Wallace Laboratories. January 1997.

5. Pelucchi A, et al. J Allergy Clin Immunol 1995;95: 515-523.

6. Weiler JM, et al. J Allergy Clin Immunol 1994;94: 972-980.

7. Gastpar H, et al. Allergy 1994;49:152-158.

8. Gambardella RA. J Internat Med Res 1993;21:268-275.