Singulair’s Mental Health Risks

Singulair (montelukast) is a prescription medication. It was FDA-approved in 1998 to prevent difficulty breathing during exercise and to treat asthma and symptoms of seasonal and year-round allergies. The drug is controversial because it’s linked to serious neuropsychiatric effects and suicidal thoughts. Some patients, including children, have died by suicide after taking the medication.

Doctors may prescribe Singulair to children because it’s available as a cherry-flavored chewable tablet. In 2018 alone, about 2.3 million children younger than 17 received a prescription. Some parents reported that their children experienced mental health effects after taking Singulair.

These reports and the FDA’s review of data led the FDA to add a boxed warning (also called a black box warning) — the agency’s most serious safety-related warning — to Singulair in 2020 for serious neuropsychiatric events.

The most prevalent side effect is a headache, and common Singulair 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.

Serious Singulair Side Effects

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

Mental Health Effects of 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.

Singulair’s mental health side effects went unnoticed for years, in part because the FDA didn’t issue its first warning and label update for the drug until 2008 — 10 years after the drug hit the market.

Although the first label update was about reported neuropsychiatric events, it wasn’t until 2020 that the FDA added the boxed warning for neuropsychiatric side effects. This warning came in response to growing postmarketing reports and parents describing these symptoms in their children.

While researchers had conducted early clinical trials on rats, such results don’t always translate directly to humans. So while these studies showed potential drug buildup in the rodents’ brains, human trials didn’t initially do so. Psychiatric effects in people can manifest slowly and inconsistently, and the drug’s original safety tests focused more on physical side effects than mental impacts.

The FDA added Singulair’s black box warning in 2020 for neuropsychiatric events. Prior to that, the agency had other label changes and advisory meetings about these side effects.

Singulair’s neuropsychiatric side effects were severe enough that Darsana Srinivasan, Chief of the Health Care Bureau in the New York Attorney General’s Office, addressed her concerns in a letter to then-FDA Commissioner Robert M. Califf in February 2024.

Srinivasan highlighted that reports showed that side effects disproportionately affect children. She said that the boxed warning added in 2020 wasn’t enough.

The Health Care Bureau Chief called on the FDA to further evaluate the risks and benefits in children under 18. Srinivasan wanted the organization to determine if the label should say the drug should not be used by children, among other actions.

While users of any age may experience Singulair’s neuropsychiatric side effects, children ages 2 through 18 are most at risk.

Researchers still aren’t sure exactly how montelukast affects the brain to cause mental health side effects, but one study in Life Sciences theorized that the drug affects brain chemicals. This is most apparent in the underdeveloped brains of children, making them more likely to suffer these side effects.

People with pre-existing mental health conditions may be at increased risk. Patients should tell their prescribers about their mental health history before taking the drug.

If you or your child experiences mood or behavior changes while taking Singulair or its generic montelukast, the FDA advises stopping the medication and contacting your healthcare provider immediately.

Make sure to document all symptoms and behaviors to discuss with your medical provider. You can report the side effects to the FDA’s MedWatch System.

If you are interested in filing a Singulair lawsuit because of serious neuropsychiatric side effects, speak to an attorney right away. Your time may be limited to file a claim.