Can abrupt discontinuation of Nasonex (mometasone furoate) nasal spray precipitate an Addisonian crisis in patients on prolonged high‑dose therapy?

Can Stopping Nasonex Cause Addisonian Crisis?

No, abrupt discontinuation of Nasonex (mometasone furoate) nasal spray does not cause Addisonian crisis in the vast majority of patients using standard therapeutic doses, because intranasal mometasone has negligible systemic absorption and does not suppress the hypothalamic-pituitary-adrenal (HPA) axis at recommended doses. 1, 2, 3

Why Nasonex Does Not Typically Cause HPA Suppression

Intranasal mometasone furoate at standard doses (100–200 mcg daily) has approximately 1% oral bioavailability and undergoes extensive first-pass metabolism, resulting in negligible systemic exposure. 1, 2 Multiple studies involving approximately 4,500 patients have demonstrated no detectable effect on HPA axis function even at doses up to 20 times the recommended daily dose. 2, 3, 4

• Cosyntropin stimulation testing in children treated with mometasone 100–200 mcg daily for up to one year showed no evidence of HPA axis suppression or adrenal insufficiency. 1, 5
• The drug's inherently low aqueous solubility limits mucosal absorption, and the swallowed portion is rapidly metabolized before reaching systemic circulation. 2
• Long-term safety studies of up to 52 weeks confirm no clinically significant systemic effects at approved doses. 1

The Rare Exception: Iatrogenic Cushing's and Secondary Adrenal Insufficiency

However, prolonged use of high-dose or supra-therapeutic intranasal corticosteroids—particularly when combined with other corticosteroid formulations—can rarely cause iatrogenic Cushing's syndrome and secondary adrenal insufficiency. 6

• A 2025 case report documented an 8-year-old who developed Cushingoid features and undetectable cortisol levels after prolonged high-dose intranasal betamethasone followed by mometasone, requiring temporary hydrocortisone replacement. 6
• This scenario requires both excessive dosing and prolonged duration beyond standard therapeutic use. 6

Clinical Algorithm: When to Worry About Adrenal Insufficiency After Stopping Nasonex

Low-Risk Patients (No Testing or Taper Needed):

• Standard dose (100–200 mcg daily) for any duration 1, 2
• No concurrent systemic or high-potency inhaled corticosteroids 7
• No clinical features of Cushing's syndrome (weight gain, moon facies, striae, hypertension) 6

Action: Discontinue Nasonex abruptly without concern for adrenal crisis. 1, 2

High-Risk Patients (Requires Endocrine Evaluation):

• Prolonged use (>6 months) of supra-therapeutic doses (>400 mcg daily) 6
• Concurrent use of potent CYP3A4 inhibitors (ritonavir, ketoconazole) that increase systemic mometasone concentrations 1
• Clinical signs of iatrogenic Cushing's syndrome: moon facies, central obesity, purple striae, hypertension, or growth deceleration in children 6
• Symptoms suggestive of adrenal insufficiency after stopping: unexplained fatigue, nausea, hypotension, hyponatremia 7

Action: Obtain morning cortisol and ACTH before discontinuation; if cortisol <250 nmol/L (<9 μg/dL) with low ACTH, perform cosyntropin stimulation test. 7 If adrenal insufficiency is confirmed (peak cortisol <500 nmol/L), initiate hydrocortisone replacement 15–25 mg daily and taper gradually over 3–6 months while monitoring HPA axis recovery. 7

Critical Pitfalls to Avoid

• Do not confuse standard-dose intranasal mometasone with systemic corticosteroids or high-potency inhaled steroids (e.g., fluticasone propionate at high doses), which carry genuine HPA suppression risk. 1, 7
• Do not delay emergency treatment if a patient presents with suspected adrenal crisis (hypotension, shock, severe vomiting)—give IV hydrocortisone 100 mg immediately, even if the only steroid exposure was intranasal. 7 While extremely unlikely with Nasonex alone, adrenal crisis is life-threatening and must never be missed. 7
• Pediatricians should schedule follow-up during prolonged high-dose nasal steroid treatment and at discontinuation, with prompt referral to pediatric endocrinology if Cushingoid features or adrenal insufficiency symptoms develop. 6

Bottom Line for Clinical Practice

For patients using Nasonex at standard doses (100–200 mcg daily), abrupt discontinuation is safe and does not require tapering or HPA axis testing. 1, 2, 3 The risk of Addisonian crisis exists only in the rare scenario of prolonged supra-therapeutic dosing combined with clinical evidence of HPA suppression. 6 When in doubt, check morning cortisol and ACTH—but for typical Nasonex users, this is unnecessary. 1, 7