What Is Theo-24 XR? Uses, Dosage, and What You Need to Know in 2026

Theo-24 XR is an extended-release formulation of theophylline, an oral bronchodilator that has been used to manage asthma and chronic obstructive pulmonary disease (COPD) for decades. It's not a new drug — theophylline has been in use since the 1950s — but it remains an important option for specific patients in 2026, particularly those who need an affordable oral bronchodilator.

What Is Theo-24 XR?

Theo-24 XR is the brand name for theophylline anhydrous in an extended-release capsule formulation designed for once-daily dosing. The "24" in the name refers to the 24-hour release profile — the medication releases slowly over an entire day, maintaining steady blood levels and providing continuous bronchodilation.

The original Theo-24 brand was manufactured by Endo Pharmaceuticals and is available in 100 mg, 200 mg, 300 mg, and 400 mg capsules. While the brand name has been largely discontinued, generic theophylline extended-release capsules and tablets (including 12-hour formulations) remain available from several manufacturers.

What Is Theo-24 XR Used For?

Theo-24 XR is FDA-approved for:

Chronic asthma: For patients with continuous or recurring symptoms who need to maintain therapeutic blood levels of theophylline throughout the day. Not for acute asthma attacks.

COPD (emphysema and chronic bronchitis): As a bronchodilator for maintenance management of symptomatic COPD.

Theophylline is not a first-line treatment per current clinical guidelines — inhaled corticosteroids (for asthma) and long-acting bronchodilators (for COPD) are preferred. However, theophylline remains valuable for patients who:

Cannot use inhalers effectively due to physical limitations.

Need an affordable oral bronchodilator (generic theophylline costs $4–$40/month).

Have not achieved adequate control with inhaled therapies alone.

Theo-24 XR Dosage

Theophylline dosing is highly individualized based on serum blood level monitoring, weight, age, smoking status, and other health conditions. Typical adult dosing for once-daily extended-release formulations:

Starting dose: 300–400 mg once daily in adults (or 10 mg/kg/day, whichever is less).

Target maintenance: Most adults require 400–1600 mg/day (wide variation exists between individuals).

Serum target: 5–15 mcg/mL (current guidelines). Blood level checks every 6–12 months for stable patients, more frequently when dose changes occur.

Because there is no single correct dose for all patients, your doctor will start low, check your blood level after 3 days, and adjust upward gradually until the target level is achieved.

How to Take Theo-24 XR

Take Theo-24 XR at the same time each morning, every day.

Do not crush or chew the extended-release capsules — swallow whole.

Avoid high-fat meals within 1 hour of taking a high dose (900 mg or more) — fat significantly increases absorption rate and can spike blood levels.

Take each dose the same way (either always with food or always without food) for consistent absorption.

Never use Theo-24 XR for an acute asthma attack. Use your rescue inhaler (short-acting bronchodilator) for sudden symptoms.

Who Should Not Take Theo-24 XR?

Theo-24 XR is not appropriate for everyone:

Allergy to theophylline or other methylxanthines (caffeine, theobromine).

Active peptic ulcer disease.

Uncontrolled seizure disorders.

Concurrent use of riociguat (contraindicated) or dipyridamole imaging tests (must separate by 24 hours).

What Does Theo-24 XR Cost in 2026?

Generic theophylline ER is one of the most affordable respiratory medications available:

Without insurance: $10–$40/month for generic ER tablets.

With GoodRx or SingleCare: As low as $4–$15/month at participating pharmacies.

With insurance: Typically $0–$15 copay as a Tier 1 preferred generic.

For a complete savings guide, see our post on how to save money on Theo-24 XR in 2026.

Is Theo-24 XR Available in 2026?

Yes, but with intermittent supply disruptions, particularly for the 400 mg strength. If you're having trouble finding it, medfinder can help you locate pharmacies near you with it in stock.