Nasonex (Mometasone Furoate)

Nasonex is a nasal corticosteroid used to manage inflammatory conditions of the nasal passages.

• Allergic rhinitis: Reduces nasal congestion, sneezing, and itching associated with seasonal or perennial allergies.
• Nasal polyps: Decreases polyp size and improves nasal airflow in patients with diagnosed nasal polyps.
• Post‑surgical nasal polyps: Helps prevent recurrence of polyps following endoscopic sinus surgery.

• Mometasone furoate acts as a high‑affinity agonist of intracellular glucocorticoid receptors. Upon binding, it modulates gene transcription, leading to decreased production of pro‑inflammatory cytokines, chemokines, and adhesion molecules in the nasal mucosa. This anti‑inflammatory activity reduces edema, mucus secretion, and cellular infiltration, thereby alleviating nasal symptoms. The localized delivery via spray limits systemic exposure while maintaining therapeutic concentrations at the site of inflammation.

Mometasone furoate nasal spray may cause a range of local and systemic adverse reactions, most of which are mild and reversible.

Common Side Effects

• Nasal irritation or burning sensation: mild discomfort that typically resolves with continued therapy.
• Epistaxis (nosebleed): occasional light bleeding from the nostrils.
• Headache: transient headache that may improve with regular use.
• Sore throat: irritation of the throat often related to spray exposure.

Serious or Rare Side Effects

• Adrenal suppression: potential reduction in endogenous cortisol production with prolonged high‑dose use.
• Glaucoma or cataract formation: increased intra‑ocular pressure or lens opacity with long‑term therapy.
• Nasal septum perforation: rare tissue loss leading to a hole in the nasal septum.

Before prescribing Nasonex, clinicians should evaluate several safety considerations to minimize risks.

• Assess for active nasal infection: avoid use in patients with untreated bacterial, fungal, or viral sinusitis.
• Pediatric use: limit to children aged 2 years and older, following approved dosing guidelines.
• Ocular monitoring: advise patients to report visual changes; monitor for glaucoma or cataract development.
• Systemic steroid exposure: consider cumulative corticosteroid load when patients use other glucocorticoids.
• Pregnancy and lactation: use only if the potential benefit justifies the potential risk to the fetus or infant.
• Store at room temperature: keep the spray in its original container, protect from moisture and direct heat.

Mometasone furoate nasal spray can interact with other medicines that affect steroid metabolism or systemic exposure.

Major Interactions (Avoid)

• Systemic corticosteroids: concurrent use may increase risk of adrenal suppression.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may raise local drug levels and enhance side effects.

Moderate Interactions (Monitor Closely)

• Antifungal azoles (e.g., fluconazole): may modestly increase exposure.
• HIV protease inhibitors (e.g., ritonavir): potential for increased systemic absorption.
• Nasal decongestant sprays: combined use may cause nasal mucosa irritation.