Singulair Side Effects

As of Mar. 31, 2024, asthma, shortness of breath and wheezing were the most common Singulair side effects reported to the FDA.

Disclaimer: Reports sent to the FDA don’t necessarily mean the drug caused an adverse event. Consult a health care professional before stopping or changing medication.

In 2020, the FDA required the makers of Singulair and generic forms of montelukast to add a black box warning — the most serious warning possible — after patients reported mental health side effects after taking Singulair.

The most prevalent side effect is a headache, but these common side effects typically disappear within the first two weeks of use.

Clinical data shows that Singulair, also known as montelukast, is a well-tolerated allergy medication with several common side effects. Serious adverse reactions are rare, even with long-term use of Singulair.

Although rare, the following serious side effect symptoms require immediate medical attention.

In some rare cases, hypersensitivity manifestations such as anaphylaxis can occur after taking Singulair.

The FDA requires a Singular black box warning for the medication due to its potential for severe mental health side effects. The black box warning applies to all users.

Some people who experienced mental health-related side effects have filed Singulair lawsuits against its drugmaker, Merck. The FDA has not recalled Singulair, which remains available as a prescription drug.

Anyone experiencing serious adverse effects should contact their doctor immediately. You can also report the problem to the FDA’s MedWatch program.

If you’re worried about mental health-related side effects from taking Singulair, consider discussing potential Singulair alternatives with your doctor.

To avoid complications with Singulair, take your medication regularly, check for drug interactions and communicate any adverse reactions with your doctor.

Some medications, such as gemfibrozil, can interact with Singulair, increasing the risk of severe side effects. Some over-the-counter drugs and supplements have adverse interactions with Singulair as well, so always check if your medications are compatible.

People with phenylketonuria should note that the chewable form of Singulair contains aspartame, which can cause health problems.

Take your medication simultaneously every day to get the best effect, and follow your prescription instructions closely. Never “double-up” if you miss a dose.

If you have a liver condition, are pregnant, trying to conceive or are nursing, it is important to consult your doctor before starting montelukast. Seek your doctor’s advice if you’re concerned about your children taking Singulair.

If you notice any mood or behavior changes, talk to your doctor immediately; it could be an early sign of serious mental health side effects.

Editor Lindsay Donaldson contributed to this article.