Singulair Side Effects: Quick Guide
If you’ve been prescribed Singulair (montelukast) for asthma or allergies, you probably expect relief, not trouble. Most people tolerate the drug well, but a handful of side effects can pop up. Knowing what to look for helps you decide if a symptom is normal or needs a doctor’s call.
Singulair works by blocking leukotrienes, chemicals that cause swelling in the airways. By stopping those chemicals, the pill eases breathing and reduces sneezing. The same action can also affect other parts of the body, which is why side effects happen.
Common side effects you might feel
Headache is one of the most reported complaints. It’s usually mild and fades after a few days. If you notice a throbbing pain that lasts longer, jot it down and mention it at your next visit.
Stomach upset, including nausea or stomach pain, shows up in some users. Taking Singulair with food can cut down on that feeling. A glass of water and a small snack often do the trick.
Some people feel a slight dizziness or a sense of being “off.” This is generally temporary, but if it interferes with driving or operating machinery, talk to your clinician.
Upper respiratory symptoms like a runny nose or sore throat can actually be the condition you’re treating, not the pill. Keep track of whether the symptom improves or worsens after starting the medication.
Rarely, mild mood changes such as irritability or mild anxiety appear. These are usually short‑lived, but if they become noticeable or last more than a week, bring them up.
When to seek medical help
Serious side effects are uncommon, but they need fast attention. Any sign of a rash that spreads, especially if it’s itchy or blistering, could signal an allergic reaction. Call your doctor right away.
Swelling of the face, lips, tongue, or throat is an emergency. This type of swelling can block airways and requires immediate medical care.
Changes in mood that feel severe—like persistent depression, thoughts of self‑harm, or extreme anxiety—are linked to montelukast in some reports. If you notice these, contact a health professional or go to the emergency department.
Blood disorders, though very rare, may show up as unusual bruising, bleeding gums, or pale skin. If you see these signs, get checked promptly.
Because side effects can vary by age, children sometimes experience different reactions. Parents should watch for unusual behavior, trouble sleeping, or new allergies and report them.
What can you do to lower the risk? Always follow the prescribed dose, never double up to make up for a missed pill, and keep a short symptom diary. If you take other meds, ask your pharmacist if any interactions could increase side effect chances.
In many cases, the benefits of Singulair—fewer asthma attacks and less nasal congestion—outweigh the mild side effects. Still, staying informed helps you act quickly if something feels off.
Bottom line: common issues like headache or stomach upset are usually harmless and fade, while rash, swelling, or severe mood changes demand urgent attention. Keep a log, stay in touch with your doctor, and you’ll get the most out of your treatment without unnecessary trouble.
