Steroid nasal sprays rarely cause side-effects. This is because they are applied directly to the nose and very little of this medicine is absorbed into the body. Therefore, they are much less likely to cause side-effects in other parts of the body. Occasionally, they cause dryness, crusting, and bleeding of the nose. If this occurs, stop it for a few days and then restart. There have been reports of nasal steroids possibly having an effect on behaviour, particularly in children. This is thought to be rare. However, a few people have reported hyperactivity, problems sleeping, anxiety, depression, and aggression.
A third study evaluated single, rising doses of Nasonex Nasal Spray, 50 mcg (1000, 2000, and 4000 mcg/day), orally administered mometasone furoate (2000, 4000, and 8000 mcg/day), orally administered dexamethasone (200, 400, and 800 mcg/day), and placebo (administered at the end of each series of doses) in 24 male volunteers (22 to 39 years of age). Dose administrations were separated by at least 72 hours. Determination of serial plasma cortisol levels at 8 AM and for the 24-hour period following each treatment were used to calculate the plasma cortisol area under the curve (AUC 0–24 ). In addition, 24-hour urinary free cortisol levels were collected prior to initial treatment administration and during the period immediately following each dose. No statistically significant decreases in the plasma cortisol AUC, 8 AM cortisol levels, or 24-hour urinary free cortisol levels were observed in volunteers treated with either Nasonex Nasal Spray, 50 mcg or oral mometasone, as compared with placebo treatment. Conversely, nearly all volunteers treated with the three doses of dexamethasone demonstrated abnormal 8 AM cortisol levels (defined as a cortisol level <10 mcg/dL), reduced 24-hour plasma AUC values, and decreased 24-hour urinary free cortisol levels, as compared to placebo treatment.