Astepro dosage timing

I have been prescibed Astepro for severe nasal allergies; what is the ideal time of day to take the medicine?  It does not seem to cause sleepness; also can it produce the oposite effect - insomnia?

Thanks,

[National Jewish Health]

Drowsiness or sleep disorders have been reported in less than 2% of those taking Astepro™ (azelastine).  The recommended dosing is twice a day – morning and evening.