Singulair (montelukast) is not a controlled substance. It carries no DEA scheduling whatsoever, meaning it is not classified alongside drugs with abuse or dependence potential like opioids, stimulants, or benzodiazepines. Singulair is, however, a prescription medication, so you still need a doctor’s authorization to obtain it.
Why Singulair Is Not a Controlled Substance
The DEA assigns controlled substance schedules (I through V) to drugs that carry a risk of abuse, physical dependence, or psychological dependence. Montelukast has none of these properties. It does not produce a high, does not cause withdrawal symptoms when stopped, and has no recreational value. Its mechanism is completely unrelated to the brain’s reward pathways.
Instead, montelukast works by blocking a specific receptor in the airways called the CysLT1 receptor. Inflammatory compounds called cysteinyl leukotrienes are released by immune cells during allergic reactions and asthma flare-ups, causing airway swelling and constriction. Montelukast prevents those compounds from binding to their target, reducing inflammation. This is a purely anti-inflammatory action with no stimulant, sedative, or mood-altering mechanism that would warrant controlled substance classification.
It Still Requires a Prescription
Even though Singulair is not a controlled substance, you cannot buy it over the counter. The FDA regulates it as a prescription-only medication because it requires medical oversight for safe use. This distinction matters: many prescription drugs (antibiotics, blood pressure medications, antidepressants) are not controlled substances but still need a doctor’s prescription. The prescription requirement exists because of the drug’s side effect profile and the need for proper diagnosis before starting treatment, not because of any abuse potential.
Singulair is available as a 10-mg tablet for adults, 4-mg and 5-mg chewable tablets for children, and 4-mg oral granules for the youngest patients. Generic montelukast is widely available and carries the same prescription requirement.
What Singulair Is Approved to Treat
Montelukast is FDA-approved for the long-term prevention of asthma attacks in adults and children one year and older. It is also approved for allergic rhinitis (seasonal and year-round nasal allergies) and for preventing exercise-induced narrowing of the airways. It is not a rescue inhaler and does not treat acute asthma attacks already in progress.
The Boxed Warning Worth Knowing About
While Singulair is not controlled, it does carry the FDA’s most serious type of warning. In March 2020, the FDA added a boxed warning about serious mental health side effects, including mood changes, agitation, sleep disturbances, and suicidal thoughts. This warning was based on an extensive review of post-market safety data and input from an outside expert panel.
As part of that decision, the FDA also narrowed its recommendation for the allergic rhinitis use specifically. For nasal allergies, montelukast should now be reserved for patients who have not responded well to, or cannot tolerate, other allergy treatments. For asthma, it remains an approved option without that restriction, though the mental health warning still applies.
The boxed warning is the primary reason some people wonder about Singulair’s legal status. Serious psychiatric side effects can sound alarming, but they reflect a safety concern rather than an abuse concern. These are fundamentally different regulatory categories. A drug can carry strong safety warnings without being scheduled as a controlled substance, and a drug can be a controlled substance without having a boxed warning. The two systems address different risks.
How Pharmacies Handle It
Because montelukast is not scheduled, pharmacies dispense it under standard prescription rules. There are no special ID requirements, no limits on how many days’ supply you can receive, and no requirement for the prescriber to use a specialized prescription pad. Refills follow normal procedures, and your pharmacist can transfer the prescription between locations without the restrictions that apply to controlled substances. If you’ve been prescribed Singulair, picking it up is no different from filling an antibiotic or a cholesterol medication.