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[Pharmacology](https://durgical.com/en/pharmacology/) · Class

# Leukotriene modifiers

Tablets that block cysteinyl leukotrienes, mediators that narrow and inflame the airways. Add-on controllers in asthma and allergic rhinitis.

Updated 2026-11-01

## What they are

Oral asthma controllers that act on the leukotriene pathway: receptor antagonists of CysLT1 (montelukast, zafirlukast) and the 5-lipoxygenase inhibitor zileuton. They are less effective than inhaled corticosteroids and are used as add-on therapy, in exercise-induced bronchoconstriction, in aspirin-exacerbated respiratory disease and in allergic rhinitis.

## Mechanism of action

Mast cells and eosinophils make leukotrienes from arachidonic acid through 5-lipoxygenase. The cysteinyl leukotrienes (LTC4, LTD4, LTE4) act on the CysLT1 receptor to contract airway muscle, increase mucus and vascular leak, and attract eosinophils. Receptor antagonists block CysLT1; zileuton stops leukotriene synthesis.

Target: Cysteinyl leukotriene receptor 1 (CYSLTR1); 5-lipoxygenase (ALOX5) for zileuton

## Key points

- Oral, add-on controllers; not for an acute attack.
- Montelukast carries a boxed warning for serious neuropsychiatric events (agitation, nightmares, depression, suicidal thinking).
- Systemic eosinophilia with vasculitis (eosinophilic granulomatosis with polyangiitis, Churg-Strauss) has been reported, often when oral steroids are tapered.
- Zileuton can injure the liver, so liver enzymes are watched; zafirlukast and zileuton raise theophylline levels.

## Drugs in this class

- [**Montelukast** An oral leukotriene receptor blocker used as an add-on asthma controller and to prevent exercise-induced… Cysteinyl leukotriene receptor 1 (CysLT1)](https://durgical.com/en/pharmacology/montelukast/)

## Others in the class

- Zafirlukast
- Zileuton
- Pranlukast

## Test yourself

Think of the answer, then tap the question to see it.

## Which receptor do montelukast and zafirlukast block?

The cysteinyl leukotriene receptor CysLT1, the receptor of LTD4.

## Which enzyme does zileuton inhibit?

5-lipoxygenase, so leukotriene synthesis from arachidonic acid stops.

## What boxed warning does montelukast carry?

Serious neuropsychiatric events, such as agitation, sleep disturbance, depression and suicidal thoughts or behaviour.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - MONTELUKAST SODIUM tablet, chewable MONTELUKAST SODIUM tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ba42b0a9-83f1-4283-a853-f99cdd0761b9) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 44 (McGraw Hill, 2023).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/leukotriene-modifiers/