Get emergency medical help if you have signs of an allergic reaction to Nasonex: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
severe bleeding or increased drainage from your nose;
nose pain or discomfort, headache;
white patches or sores in the nose that won't heal;
wheezing, trouble breathing;
vision problems;
ear pain or full feeling, trouble hearing, drainage from the ear.
Steroid medicine can affect growth in children. Tell your doctor if your child is not growing at a normal rate while using Nasonex.
Although the risk of serious side effects is low when mometasone is used in the nose, side effects can occur if the medicine is absorbed into your bloodstream. Tell your doctor if you have possible signs of long-term steroid use:
weight gain (especially in your face or your upper back and torso);
slow wound healing, thinning skin, increased body hair;
irregular menstrual periods, changes in sexual function; or
muscle weakness, tired feeling, depression, anxiety, or feeling irritable.
Common Nasonex side effects may include:
nosebleeds;
headache;
stuffy nose, sore throat, cough; or
flu-like symptoms.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Nasonex side effects (more detail)
