Azelastine hydrochloride displayed no sensitising potential in the guinea pig. Azelastine demonstrated no genotoxic potential in a battery of in vitro and in vivo tests, nor any carcinogenic potential in rats or mice. In male and female rats, azelastine at oral doses greater than 3 mg/kg/day caused a dose-related decrease in the fertility index; no substance-related alterations were found in the reproductive organs of males or females during chronic toxicity studies, however, embryotoxic and teratogenic effects in rats, mice and rabbits occurred only at maternal toxic doses (for example, skeletal malformations were observed in rats and mice at doses of mg/kg/day).
It may take up to 4 weeks for the ears to start feeling normal. One must also try to pop the ears immediately after nasal spray use and every hour while awake throughout this period of time. When one tries to pop the ears, try to blow out your nose with your nose pinched shut with your fingers. Popping the ears in this manner, esp after nasal spray use helps to squeeze some of the medication into the eustachian tube. Do not exceed the pressure one uses as if you have mild constipation. Swallowing or yawning does not work as well in this situation.