Two medicines, side by side
Montelukast vs theophylline
Montelukast and theophylline are both labeled for asthma. Drugs@FDA records approvals of montelukast since 1998 and of theophylline since 1982. Pharmacies paid $0.0419 per montelukast sod 10 mg tablet and $0.330 per theophylline ER 300 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like. Theophylline's other strengths are brand-only: $3.82 per Theo-24 ER 100 mg capsule. In FDA's classes, montelukast is a leukotriene receptor antagonist and theophylline a methylxanthine.
Check it at the source: the montelukast FDA label on DailyMed (effective April 30, 2025); the theophylline FDA label on DailyMed (effective March 10, 2026).
Highlights of the montelukast record
Montelukast (Singulair) · label of April 30, 2025
SERIOUS NEUROPSYCHIATRIC EVENTS Serious neuropsychiatric (NP) events have been reported with the use of SINGULAIR. The types of events reported were highly variable, and included, but were not limited to, agitation, aggression, depression, sleep disturbances, suicidal thoughts and behavior (including suicide). The mechanisms underlying NP events associated with SINGULAIR use are currently not well understood [see Warnings and Precautions (5.1) ].
Used for
From the label: indicationsSINGULAIR is a leukotriene receptor antagonist indicated for: Prophylaxis and chronic treatment of asthma in patients 12 months of age and older ( 1.1 ). Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 6 years of age and older ( 1.2 ). […]
On the market
- Earliest approval on file
- February 20, 1998
- Generic labelers
- 36 labelers
- Pharmacy cost
- $0.0419 per tablet
Supply and safety
- Shortage
- A presentation being discontinued
- Recalls
- 11
Highlights of the theophylline record
Theophylline (Theo) · label of March 10, 2026
Used for
From the label: indicationsTheophylline extended-release tablets are indicated for the treatment of the symptoms and reversible airflow obstruction associated with chronic asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.
On the market
- Earliest approval on file
- July 26, 1982
- Generic labelers
- 26 labelers
- Pharmacy cost
- $0.330 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 4
Source: FDA drug labels via openFDA (Montelukast label of April 30, 2025, Theophylline label of March 10, 2026); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do montelukast and theophylline differ on the record?
In FDA's classes, montelukast is a leukotriene receptor antagonist and theophylline a methylxanthine.
How each works, in its label's words: Montelukast, “These eicosanoids bind to cysteinyl leukotriene (CysLT) receptors.”; Theophylline, “Mechanism of Action: Theophylline has two distinct actions in the airways of patients with reversible obstruction; smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of …”
Half-life, in each label's words: Montelukast, “In several studies, the mean plasma half-life of montelukast ranged from 2.7 to 5.5 hours in healthy young adults.”; Theophylline, “At steady-state, on a dosage regimen with 6-hour intervals, the expected mean trough concentration is approximately 60% …”
Only the montelukast label carries a boxed warning.
Generics: montelukast since 2012; theophylline since 1976 (Drugs@FDA).
| Montelukast | Theophylline | |
|---|---|---|
| Labeled for | Asthma, Allergies | Asthma |
| Pharmacologic class | Leukotriene Receptor Antagonist | Methylxanthine |
| How it works (label) | The cysteinyl leukotrienes (LTC 4 , LTD 4 , LTE 4 ) are products of arachidonic acid metabolism and are released from various cells, including mast cells and eosinophils. These eicosanoids bind to cysteinyl leukotriene (CysLT) receptors. | Mechanism of Action: Theophylline has two distinct actions in the airways of patients with reversible obstruction; smooth muscle relaxation (i.e., bronchodilation) and suppression of the response of the airways to stimuli (i.e. … |
| Half-life (label) | In several studies, the mean plasma half-life of montelukast ranged from 2.7 to 5.5 hours in healthy young adults. | At steady-state, on a dosage regimen with 6-hour intervals, the expected mean trough concentration is approximately 60% of the mean peak concentration, assuming a mean theophylline half-life of 8 hours. |
| Earliest approval on file (Drugs@FDA) | February 20, 1998 | July 26, 1982 |
| First generic approved | August 3, 2012 | July 26, 1976 |
| Generic labelers (NDC) | 36 labelers | 26 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0419 per tablet (Montelukast sod 10 mg tablet) | $0.330 per tablet (Theophylline ER 300 mg tablet) |
| 12-month price change | -20% | -33% |
| Boxed warning | Yes | No |
| Shortage now | A presentation being discontinued | No current entry |
| Recalls recorded | 11 | 4 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 174,997 | 12,327 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Montelukast label, drug interactionsDRUG INTERACTIONS No dose adjustment is needed when SINGULAIR is co-administered with theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, thyroid hormones, sedative hypnotics, non-steroidal anti-inflammatory agents, benzodiazepines, decongestants, and Cytochrome P450 (CYP) enzyme inducers [see Clinical Pharmacology (12.3) ].
Source: FDA drug labels via openFDA
What next?
- Alternatives to montelukast
- every medicine labeled for the same conditions