Montelukast (Singulair)

Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.

About Montelukast

What it is

Montelukast is a leukotriene receptor antagonist: it blocks the receptor for cysteinyl leukotrienes, inflammatory signals that narrow the airways and cause swelling and mucus. It is taken as a daily tablet for asthma, to prevent exercise-induced airway narrowing, and for allergic rhinitis. It is sold as Singulair, among other names.

How genes come into it

Montelukast is absorbed from the gut partly by the transporter SLCO2B1 and broken down mainly by CYP2C8, with help from UGT1A3; studies have linked variants in these to its blood levels. Other studies looked at genes of the leukotriene pathway (ALOX5, LTA4H, LTC4S) for how well it controlled asthma. The findings come from single or a few studies, and there is no CPIC or DPWG guideline.

What research found

Every published finding on gene variants and Montelukast. Upload your DNA file to see which of these rows apply to you.

Rated evidence (15 rated variants)

PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.

SLCO2B1 rs12422149: Level 3. Efficacy: Asthma. 2.

ABCC1 rs119774: Level 3. Efficacy: Asthma. 1.

ALOX5 rs2115819: Level 3. Efficacy: Asthma. 1.

LTA4H rs2660845: Level 3. Efficacy: Asthma. 1.

Metabolism (9 findings)

Studies of how quickly the body processes this medication.

ABCC9 rs704212: Allele T is associated with decreased concentrations of montelukast in healthy individuals as compared to allele C.

CYP2C8 CYP2C8*1, CYP2C8*3: CYP2C8 *3 is associated with decreased concentrations of montelukast in healthy individuals as compared to CYP2C8 *1/*1.

CYP2C8 CYP2C8*1, CYP2C8*4: CYP2C8 *4 is associated with increased concentrations of montelukast in healthy individuals as compared to CYP2C8 *1/*1.

UGT1A3 UGT1A3*1, UGT1A3*2: UGT1A3 *2 is associated with decreased concentrations of montelukast in healthy individuals as compared to UGT1A3 *1/*1.

Response (9 findings)

Studies of how well it worked in people carrying a variant.

rs1786929: Genotypes AA + AG is associated with increased response to fluticasone propionate or montelukast in children with Asthma as compared to genotype GG.

CA10 rs967676: Genotypes CC + CT is associated with increased response to fluticasone propionate or montelukast in children with Asthma as compared to genotype TT.

CYP2C8 rs11572080: Genotype CC is associated with increased clinical benefit to corticosteroids or montelukast in children with Asthma as compared to genotypes CT + TT.

MLLT3 rs6475448: Genotype AA is associated with increased response to montelukast in people with Asthma as compared to genotype GG.

Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.

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Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.

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Content updated September 2026.

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