Nasonex Side Effects: Complete Safety Guide

Common Side Effects of Nasonex

Based on the Patient Information Leaflet and clinical data, the following side effects have been reported:

• Very common (may affect more than 1 in 10 people): Nosebleeds – particularly in patients using Nasonex twice daily for nasal polyps.
• Common (may affect up to 1 in 10 people): Headache, sneezing, sore throat, ulcers in the nose, respiratory tract infection.
• Not known (frequency cannot be estimated from available data): Increased pressure in the eye (glaucoma), cataracts, blurred vision, damage to the nasal septum (the partition inside the nose), changes in taste and smell, difficulty breathing or wheezing.

Long‑term use of high doses of corticosteroid nasal sprays may rarely cause systemic effects, such as slowed growth in children or adrenal suppression, but this is extremely uncommon with Nasonex due to minimal absorption.

When Do Nasonex Side Effects Start?

The onset of side effects depends on the type:

• Local irritant effects (e.g., sneezing, mild burning, or stinging) can occur immediately after spraying or within the first few days of use. These often settle as your nose adjusts.
• Nosebleeds may appear after several days of use, especially if the nasal mucosa becomes dry. They are more frequent with twice‑daily dosing.
• Systemic effects (e.g., glaucoma, cataracts, growth suppression) are not immediate; they would only develop after months or years of high‑dose use.
• Hypersensitivity reactions (rare) can occur within minutes to hours after any dose.

If you experience sudden severe symptoms, stop using and seek medical attention immediately.

How Long Do Nasonex Side Effects Last?

The duration varies by side effect:

• Mild local irritation, sneezing, or headache: Usually transient and resolve within minutes to hours; if persistent, they often improve as your body gets used to the spray (within a few days).
• Nosebleeds: If minor, they may stop quickly. If recurrent, they can persist while using the spray; reducing the dose or stopping (under medical advice) usually resolves them.
• Nasal ulcers or soreness: These heal within a few days after stopping the spray; good nozzle hygiene can prevent them.
• Systemic effects (rare): If they occur (e.g., visual changes from glaucoma), they may take longer to resolve and require specialist management.

Most side effects are reversible upon discontinuation. Always consult your doctor if symptoms persist.

Side Effects Timeline: Acute vs Long‑Term

Contraindications: Who Should Not Use Nasonex

Do not use Nasonex if:

• You are allergic to mometasone furoate or any of the other ingredients (see section 6 of PIL).
• You have an untreated infection in your nose (e.g., herpes, bacterial or fungal infection). The infection must be treated first.
• You have recently had nasal surgery or injured your nose – wait until it has healed completely.

Consult your doctor before use if:

• You have or have ever had tuberculosis.
• You have any other infection (e.g., systemic fungal, bacterial, viral).
• You are taking other corticosteroid medicines (oral, injectable, or other nasal sprays).
• You have cystic fibrosis.
• You are immunocompromised or have been in contact with measles or chickenpox.
• You are pregnant, planning pregnancy, or breastfeeding.

Food Interactions and Other Medicines

Food interactions: No interactions with food have been reported. Nasonex can be taken without regard to meals.

Drug interactions:

• Other corticosteroids: Using Nasonex alongside oral, injectable, or other nasal corticosteroids may increase the risk of systemic effects. Your doctor may adjust doses.
• HIV medications (ritonavir, cobicistat): These are strong CYP3A4 inhibitors and may increase systemic exposure to mometasone. Monitor closely if concomitant use is necessary.
• Other CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): Caution advised, though clinical significance is low due to minimal absorption.

Always tell your doctor or pharmacist about all medicines you take, including herbal products and over‑the‑counter drugs.

Nasonex Side Effects FAQs

Need Nasonex or Advice on Allergy Treatment?

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