Alternatives to Zyflo If You Can't Fill Your Prescription

Zyflo (zileuton) is a unique asthma medication with a mechanism no other drug fully replicates. But if your pharmacy doesn't stock it, your insurance won't cover it, or the cost is prohibitive, you need to know your options. This guide covers the best alternatives to Zyflo — what they do, how they compare, and what questions to ask your doctor before switching.

Important: Never stop or switch asthma medications without talking to your prescriber first. Asthma can worsen quickly without proper controller therapy.

What Makes Zyflo Unique — and What You'd Be Replacing

Zyflo is the only FDA-approved 5-lipoxygenase (5-LOX) inhibitor in the United States. It works by blocking the enzyme that produces leukotrienes — the inflammatory molecules that cause airway swelling, constriction, and mucus production in asthma. This upstream blockade prevents the formation of all four major leukotrienes (LTB4, LTC4, LTD4, and LTE4).

By contrast, montelukast and zafirlukast — the other leukotriene modifiers — block leukotriene receptors rather than stopping leukotriene production. This distinction matters most for patients with aspirin-exacerbated respiratory disease (AERD), where leukotriene overproduction is a central driver of symptoms. In a 2015 patient survey, 28% of AERD patients rated Zyflo as 'extremely effective' versus 15% for montelukast.

Alternative #1: Montelukast (Singulair)

Montelukast is the most widely prescribed leukotriene modifier and the most likely substitute a doctor would suggest when Zyflo isn't available. It is a leukotriene receptor antagonist (LTRA) — it blocks cysteinyl leukotriene receptors rather than stopping leukotriene production.

Dosing: Once daily (much simpler than Zyflo's 2-4x/day dosing)

Ages: Approved from 12 months old for asthma

Liver monitoring: Not required (unlike Zyflo)

Cost: Generic available; typically $10-$30 per month with discount cards

Watch for: FDA black box warning for neuropsychiatric events (anxiety, depression, suicidal thoughts — rare but serious)

Montelukast is generally effective for mild-to-moderate persistent asthma and is far more accessible and affordable than Zyflo. However, because it works on receptors rather than synthesis, it may be less effective for AERD patients.

Alternative #2: Zafirlukast (Accolate)

Zafirlukast is another LTRA like montelukast but with slightly different pharmacology. It is often considered the closest alternative to Zyflo in the leukotriene modifier class.

Dosing: Twice daily, taken on an empty stomach

Ages: Approved for ages 5 and older

Liver monitoring: Recommended; hepatotoxicity risk similar to Zyflo (rare but documented)

Cost: Generic available; typically $25-$60 per month with discount cards

Zafirlukast is less widely used than montelukast, but its twice-daily dosing makes it more manageable than Zyflo's 4x/day immediate-release regimen. Like montelukast, it blocks receptors rather than production — still a meaningful step down for AERD patients.

Alternative #3: Inhaled Corticosteroids (ICS)

Inhaled corticosteroids (ICS) are the gold standard for persistent asthma and are more effective than any leukotriene modifier for improving lung function. If you're not already on an ICS, your doctor may start or increase one while you work on accessing Zyflo.

Examples: Fluticasone (Flovent, Arnuity Ellipta), budesonide (Pulmicort), beclomethasone (Qvar)

Dosing: Typically 1-2 puffs twice daily, inhaled

Side effects: Oral thrush (candidiasis), dysphonia; rinse mouth after use

Cost: Generics available; often $20-$60/month or lower with insurance

Alternative #4: ICS-LABA Combinations (for Moderate-to-Severe Asthma)

If your asthma is moderate to severe and not controlled by an ICS alone, a combination ICS-LABA inhaler may be what your doctor recommends. These pair a corticosteroid with a long-acting bronchodilator for stronger, broader control.

Examples: Symbicort (budesonide/formoterol), Advair Diskus (fluticasone/salmeterol), Breo Ellipta (fluticasone/vilanterol)

Note: Long-acting beta-agonists (LABAs) should never be used as monotherapy for asthma due to increased risk of serious asthma-related events. They are only appropriate in combination with ICS.

Which Alternative Is Right for You?

The best alternative to Zyflo depends on why you're taking it in the first place. Here's a quick framework:

If you have AERD (aspirin-sensitive asthma): Montelukast is the closest available substitute, though less effective. Work with your allergist to optimize your regimen.

If you use Zyflo as add-on therapy: Your doctor may increase your ICS dose as a temporary measure while you locate Zyflo.

If cost is the main barrier: Discount coupons can reduce Zyflo CR to approximately $260-$315/month — potentially keeping you on Zyflo rather than switching. See our savings guide.

Before You Give Up on Zyflo

If your pharmacist can't fill your Zyflo prescription, don't assume it's unavailable everywhere. Try medfinder — a service that calls pharmacies near you to check which ones have Zyflo in stock and can fill your prescription. You may find a pharmacy within a few miles that carries it. Switching medications should always be a last resort and done only with your doctor's guidance.

See also: How to Find Zyflo in Stock Near You (Tools + Tips)