Along with its needed effects, mometasone may cause some unwanted or undesirable effects. Generally, mometasone is well tolerated and many people will not experience unwanted effects. The frequency and severity of these effects is dependent on many factors including dose, duration of therapy and individual susceptibility. Possible unwanted effects include:

• Nose/throat dryness or irritation
• blood-tinged mucus/phlegm
• nosebleeds 

Tell your doctor right away if any of these serious side effects occur:

• pain/sores in your nose
• white patches in your nose/mouth
• painful swallowing/trouble swallowing.  
• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

Mometasone furoate is a corticosteroid used to treat swelling and inflammation in the breathing passages.

Before using mometasone, tell your doctor or pharmacist if you are allergic to it or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: eye problems (such as glaucoma, cataracts), infections (including tuberculosis, herpes eye infection), recent nose problems (such as injury, ulcers, surgery).  Rarely, using corticosteroid medications for a long time can make it more difficult for your body to respond to physical stress. Therefore, before having surgery or emergency treatment, or if you get a serious illness/injury, tell your doctor or dentist that you are using this medication or have used this medication within the past few months.

Use in pregnancy and breastfeeding: It is unlikely that enough mometasone is absorbed into the blood or appears in breastmilk to cause any concerns, however, human data is limited.  Consult your doctor or pharmacist before use.