Understanding Dulera Side Effects

Dulera (mometasone furoate/formoterol fumarate) is a combination inhaler used to control asthma in patients 5 years and older. Like all medications, it can cause side effects. Most are mild and manageable, but some require immediate medical attention.

This guide covers the most common and serious side effects of Dulera, what you can do about them, and when to contact your doctor. If you're new to Dulera, start with our overview of what Dulera is and how it's used.

Common Side Effects of Dulera

These side effects occur in a notable percentage of Dulera users during clinical trials. They're usually mild and may improve as your body adjusts to the medication:

Nasopharyngitis (Nose and Throat Irritation)

This is the most commonly reported side effect. You may feel like you have a mild cold — stuffy nose, sore throat, or post-nasal drip. It usually resolves on its own. Over-the-counter saline nasal spray can help.

Sinusitis

Some patients develop sinus infections while on Dulera. If you have facial pain, thick nasal discharge, or symptoms lasting more than 10 days, see your doctor.

Headache

Headaches are common, especially when first starting Dulera. Over-the-counter pain relievers like acetaminophen or ibuprofen usually help. If headaches are severe or persistent, talk to your doctor.

Oral Candidiasis (Thrush)

The corticosteroid component (mometasone) can cause a yeast infection in your mouth and throat. Signs include white patches on your tongue, inner cheeks, or throat, and sometimes a cottony feeling in your mouth.

How to prevent thrush:

• Rinse your mouth thoroughly with water after every use of Dulera — swish, gargle, and spit
• Do not swallow the rinse water
• Use a spacer if recommended by your doctor
• Brush your teeth after using your inhaler when possible

Hoarseness (Dysphonia)

The inhaled corticosteroid can irritate your vocal cords, making your voice raspy or weak. Rinsing your mouth after use helps. If hoarseness persists, your doctor may adjust your dose.

Upper Respiratory Infections

Common colds and upper respiratory infections are reported more frequently with Dulera use. This may be partly related to the mild immunosuppressive effect of the corticosteroid component.

Serious Side Effects: When to Call Your Doctor

The following side effects are less common but require prompt medical attention:

Boxed Warning: Risk of Asthma-Related Death

Dulera contains formoterol, a long-acting beta2-agonist (LABA). LABAs carry a boxed warning — the FDA's most serious warning — about an increased risk of asthma-related death. This risk is highest when a LABA is used without an inhaled corticosteroid. Since Dulera combines both medications in one inhaler, this risk is reduced compared to using a LABA alone, but it's important to be aware of it.

Key points:

• Dulera should only be used when asthma is not adequately controlled on an ICS alone
• Once asthma is well-controlled, your doctor may step you down to an ICS-only inhaler
• Never use Dulera as a rescue inhaler for sudden breathing problems

Severe Allergic Reactions

Rarely, Dulera can cause serious allergic reactions including:

• Swelling of the face, lips, tongue, or throat (angioedema)
• Difficulty breathing or swallowing
• Severe skin rash or hives

If you experience any of these, call 911 or go to the emergency room immediately.

Paradoxical Bronchospasm

In rare cases, Dulera can cause your airways to tighten instead of open — the opposite of what it's supposed to do. If you start wheezing or have trouble breathing right after using Dulera, stop using it and use your rescue inhaler. Contact your doctor right away.

Adrenal Insufficiency

Long-term use of inhaled corticosteroids, or switching from oral steroids to Dulera, can suppress your adrenal glands. Symptoms include:

• Extreme fatigue
• Weakness
• Nausea or vomiting
• Low blood pressure
• Dizziness

Your doctor should monitor you carefully if you're transitioning from oral corticosteroids to Dulera.

Bone Density Loss

Inhaled corticosteroids can reduce bone mineral density over time, increasing the risk of osteoporosis and fractures. This is more of a concern with long-term use and higher doses. Talk to your doctor about bone health monitoring if you'll be on Dulera long-term.

Eye Problems

Long-term use may increase the risk of glaucoma and cataracts. Report any changes in vision, eye pain, or blurred vision to your doctor promptly.

Growth Effects in Children

Inhaled corticosteroids, including the mometasone in Dulera, may slow growth in children. Your child's doctor should monitor their height regularly. The benefits of asthma control generally outweigh this risk, but it should be tracked.

Cardiovascular Effects

Formoterol can increase heart rate, raise blood pressure, and affect heart rhythm. Contact your doctor if you notice:

• Fast or irregular heartbeat
• Chest pain
• Tremors
• Nervousness

These effects are more likely if you're also taking other medications that affect the heart. Review Dulera's drug interactions with your doctor.

Infections

Because Dulera has immunosuppressive properties, you may be more susceptible to infections, including chickenpox and measles. If you haven't had these illnesses or been vaccinated, avoid exposure. Contact your doctor if you're exposed.

Side Effects by Frequency

Here's a quick breakdown to put things in perspective:

• Very common (10%+ of users): Nasopharyngitis
• Common (1-10%): Sinusitis, headache, influenza, oral thrush, hoarseness, upper respiratory infection
• Uncommon to rare (<1%): Paradoxical bronchospasm, severe allergic reactions, adrenal insufficiency, significant cardiovascular effects
• Long-term risks: Bone density loss, cataracts, glaucoma, growth suppression in children

Tips for Managing Dulera Side Effects

1. Always rinse your mouth after using Dulera. This single habit prevents the most common preventable side effects (thrush and hoarseness).
2. Take it at the same times daily — morning and evening, about 12 hours apart. Consistent use helps your body adjust.
3. Don't skip doses to avoid side effects. Stopping suddenly can worsen your asthma. Talk to your doctor first.
4. Keep a side effects diary for the first few weeks. Note any new symptoms so you can discuss them at your next appointment.
5. Know the difference between Dulera (controller) and your rescue inhaler. Dulera is not for sudden attacks.

When to Call Your Doctor vs. When to Call 911

Call your doctor if you experience:

• Persistent headache or hoarseness that doesn't improve
• Signs of thrush that don't respond to mouth rinsing
• Increased asthma symptoms despite regular use
• Signs of infection (fever, chills, body aches that don't resolve)
• Changes in vision

Call 911 or go to the ER if you experience:

• Severe difficulty breathing
• Swelling of face, lips, tongue, or throat
• Chest pain or rapid irregular heartbeat
• Severe dizziness or fainting

Talk to Your Doctor About the Full Picture

Every medication involves tradeoffs. Dulera helps millions of people control their asthma and breathe easier. Most side effects are mild and manageable. The serious ones are rare but important to know about.

Understanding how Dulera works can help you make sense of its side effects. And if you're concerned about cost while managing your treatment, our guide on saving money on Dulera can help.

If you're ready to fill your prescription, MedFinder can help you find Dulera in stock near you.