Is Singulair an antihistamine?
Short answer
Medication question
No. Singulair is not an antihistamine. Its active ingredient, montelukast, is a leukotriene receptor antagonist that blocks leukotrienes rather than histamine. It is used for allergic rhinitis and asthma, and carries an FDA boxed warning for mood and behavior changes.
This is a general research summary, not medical advice. A pharmacist can confirm it for your situation.
Key facts
Singulair's active ingredient, montelukast, is a leukotriene receptor antagonist, not an antihistamine.
Antihistamines relieve allergy symptoms by blocking histamine at H1 receptors, a different mechanism from Singulair.
Antihistamines for allergies — MedlinePlus (U.S. National Library of Medicine)
Allergic rhinitis can be managed with several medication classes, and treatment choice depends on symptoms and response.
Here's the nuance
A one-liner rarely tells the whole story. This is the honest detail behind the short answer above.
Singulair is the brand name for montelukast, which belongs to a drug class called leukotriene receptor antagonists. Antihistamines work by blocking histamine at H1 receptors, but montelukast works on a completely different chemical, leukotrienes. Leukotrienes are inflammatory molecules your body releases during an allergic response and in asthma, causing airway tightening, mucus, and congestion. Because Singulair targets that separate pathway, it is not an antihistamine.\n\nDoctors prescribe Singulair for asthma and for allergic rhinitis (hay fever) symptoms. Unlike fast-acting oral antihistamines such as loratadine or cetirizine, it is taken once daily as a preventive controller and does not deliver the quick, on-demand itch and sneeze relief people expect from an H1 antihistamine. Some people take Singulair alongside an antihistamine because the two act on different parts of the allergic reaction.\n\nSingulair carries an FDA boxed warning, the agency's most serious warning, about neuropsychiatric events including agitation, depression, sleep problems, and suicidal thoughts or actions. Because of this, the FDA advises reserving montelukast for allergic rhinitis in people who cannot tolerate or respond to other therapies. Talk to your doctor or pharmacist about the benefits and risks before starting it.\n\nLike antihistamines, Singulair does not treat anaphylaxis. A severe, life-threatening allergic reaction requires epinephrine and emergency care, not montelukast or any oral allergy pill.
The key points
The handful of things that decide the answer — skim these if you only read one section.
Not an antihistamine
Singulair (montelukast) is a leukotriene receptor antagonist, a separate drug class from antihistamines.
Different target
It blocks leukotrienes, not histamine, so it works through a different part of the allergic response.
Preventive, not on-demand
It is taken once daily as a controller for asthma and hay fever, not for quick symptom relief.
FDA boxed warning
Montelukast carries the FDA's strongest warning for serious mood and behavior changes.
Not for anaphylaxis
Singulair does not treat severe allergic reactions, which require epinephrine and emergency care.
Please read before acting on this
General information — not medical advice
This page is a general research summary about the medication in question. It does not account for your specific health, other medicines you take, or your dose, and it can go out of date. It is not medical advice, a prescription, or a substitute for professional judgment.
Ask your pharmacist or prescriber before starting, stopping, changing, or continuing any medication — they can check it against your situation in minutes.
❓Frequently Asked Questions
Singulair is a leukotriene receptor antagonist. Its active ingredient, montelukast, blocks leukotrienes, inflammatory chemicals involved in asthma and allergies. This makes it different from antihistamines, decongestants, and steroids. It is taken once a day as a maintenance medication.
Many people are prescribed Singulair alongside an antihistamine because the two work on different pathways of the allergic reaction. This can be done under a doctor's guidance. Always confirm the combination with your doctor or pharmacist, especially if you take other medications. Do not start or stop either drug without medical advice.
Singulair carries an FDA boxed warning because of reports of serious neuropsychiatric effects, including agitation, depression, sleep disturbances, and suicidal thoughts or actions. The FDA recommends it for hay fever only when other treatments are not suitable. Watch for any mood or behavior changes and contact your doctor right away if they occur.
Singulair does not typically cause the sedation associated with first-generation antihistamines like Benadryl, because it does not block histamine in the brain. However, it can affect mood and sleep as noted in its FDA warning. If you notice unusual drowsiness, insomnia, or mood changes, tell your doctor. Everyone responds differently.
Reviewed by
Curex Editorial TeamReviewed for accuracy
Last reviewed August 2026
Related Articles
Can Allegra cause dizziness?
Allegra (fexofenadine) can occasionally cause dizziness, though it's not common. Learn why it happens, who's most at risk, and when to contact your doctor.
Read moreDoes Aetna cover vaccinations and immunizations?
Yes — Aetna covers ACIP-recommended vaccines at $0 in-network under ACA rules. Medicare Part B covers flu, COVID-19, and pneumococcal at $0.
Read moreDoes Cigna cover durable medical equipment?
Cigna covers medically necessary DME like CPAP and wheelchairs when prescribed by a doctor. Prior auth and in-network suppliers are required.
Read moreDoes Humana offer coverage for infertility treatments?
Humana infertility coverage varies by plan and state. Diagnostics are more often covered than IVF. State mandates may require coverage for some plans.
Read moreCan Allegra make you sleepy?
Allegra is non-drowsy and rarely causes sleepiness. A small number of people do feel mild fatigue. Far less sedating than Benadryl.
Read moreStop guessing which trigger is behind it
If your symptoms keep coming back and an allergen might be the cause, testing tells you what you actually react to. Curex offers at-home allergy testing and immunotherapy so you can treat the trigger, not just manage the symptom.
- At-home allergy test kit — no clinic visit
- Reviewed by board-certified allergists
- Find the trigger instead of guessing
This content is for general informational purposes only. It is not medical advice, a prescription, or a substitute for professional judgment, and it does not account for your health, other medications, or dose. Always ask your pharmacist or prescriber before starting, stopping, or changing any medication.