Yes, you can take azelastine as-needed for symptom relief. Azelastine is rapid-acting and typically starts working within 15 minutes. Taking azelastine as-needed will lead to a temporary improvement in sneezing and itchy and runny nose. However, the effects of the medication will wear off after 12 hours, so if you need continuous symptom relief it is recommended you take the medication twice daily. Using azelastine twice daily may also lead to an improvement in overall congestion.