Updated: January 17, 2026

Theo-24 XR Shortage: What Providers and Prescribers Need to Know in 2026

Author

Peter Daggett

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Current Supply Status (2026)
Clinical Implications of Therapy Gaps
Serum Level Targets: Updated Guidance
Prescribing Strategies During the Shortage
Therapeutic Alternatives Summary
Tools to Help Your Patients Access Theophylline

A clinical briefing for providers on the Theo-24 XR shortage in 2026: availability data, prescribing implications, therapeutic alternatives, and patient access tools.

The theophylline extended-release supply shortage — affecting the Theo-24 XR formulation and generic equivalents — has evolved from an intermittent disruption to a persistent clinical reality. As of early 2026, prescribers managing patients on long-term theophylline therapy need to be aware of current supply constraints, clinical implications of gaps in therapy, and available alternatives.

This clinical update summarizes the current shortage status, management considerations, and tools to support patient access.

Current Supply Status (2026)

The ASHP shortage listing for Theophylline 24-Hour Extended Release Capsules and Tablets has been active since August 2023, with the most recent update in September 2025. Key supply data:

Endo Pharmaceuticals: Theo-24 400 mg capsules (NDC 52244-0400-10) affected by intermittent availability issues.

Glenmark: 400 mg and 600 mg tablets on back order as of September 2025; no estimated release date. Voluntary recall of multiple 400 mg batches in August 2025 due to dissolution failures.

Rhodes: 400 mg extended-release tablets on back order; no estimated release date.

Lower strengths (100–300 mg): Generally more available, though spot shortages occur.

Clinical Implications of Therapy Gaps

For patients stabilized on theophylline, supply disruptions pose several clinical risks:

Subtherapeutic levels: Missing doses or switching to lower strengths without proper dose adjustment may result in serum concentrations below the therapeutic range (target: 5–15 mcg/mL per current guidelines), leading to worsened symptom control.

Manufacturer switching risk: Extended-release formulations from different manufacturers may have different dissolution profiles. Current GDUFA standards require bioequivalence, but real-world variation in release kinetics can affect serum levels. When a patient changes manufacturers, recheck serum theophylline within 3–5 days.

COPD exacerbation risk: Patients using theophylline as their only bronchodilator are at elevated risk during supply gaps. Ensure these patients have rescue medications and a contact plan.

Serum Level Targets: Updated Guidance

Current clinical guidelines generally recommend targeting serum theophylline concentrations of 5–15 mcg/mL for most patients, which is lower than the traditional 10–20 mcg/mL range. This revised target balances efficacy with reduced toxicity risk, particularly for the CNS and cardiovascular effects that occur more frequently at higher concentrations.

Prescribing Strategies During the Shortage

Consider the following approaches for patients who cannot obtain their usual theophylline supply:

Prescribe for available strengths. If 400 mg is unavailable, write for two 200 mg capsules once daily (equivalent total daily dose). Verify and recheck serum levels within 3–5 days.

Switch to 12-hour formulations when available. Some 12-hour extended-release tablets (e.g., 300 mg, 450 mg) remain more available. Twice-daily dosing may introduce more peak-trough variation; monitor accordingly.

Document clinical rationale for continued theophylline use. For patients where theophylline is specifically preferred (cost barrier to inhaled therapies, inability to use inhalers), documenting the medical necessity facilitates prior authorization for alternatives if needed.

Consider transition to inhaled therapy. For COPD patients, tiotropium (Spiriva) or an ICS/LABA combination is typically preferred by current GOLD guidelines over theophylline. For asthma patients, inhaled corticosteroids remain the cornerstone of maintenance therapy.

Therapeutic Alternatives Summary

COPD: Tiotropium (LAMA), combination LAMA/LABA (e.g., Anoro Ellipta, Duaklir), ICS/LABA (e.g., Advair, Symbicort).

Asthma: Inhaled corticosteroids (ICS) as first-line; add LABA or LTRA (montelukast) as step-up therapy.

Oral alternative: Dyphylline — same class as theophylline, wider safety margin, no TDM required, available orally.

Tools to Help Your Patients Access Theophylline

When your patients can't find theophylline, medfinder for Providers is a resource worth sharing. medfinder calls pharmacies near the patient's location to check real-time availability, then texts the patient a list of pharmacies that can fill the prescription. This reduces the call burden on both patients and office staff.

For a detailed guide on helping your patients find theophylline in stock, see our provider's guide to finding Theo-24 XR in stock.

Frequently Asked Questions

Current guidelines generally recommend targeting 5–15 mcg/mL for most patients, lower than the traditional 10–20 mcg/mL range. This balance achieves most of the therapeutic benefit while minimizing the risk of toxicity, particularly cardiovascular and CNS effects that become more frequent at higher concentrations.

Yes, with caution. Extended-release theophylline products from different manufacturers may have different dissolution profiles. Recheck serum theophylline concentrations within 3–5 days of any manufacturer switch and adjust dosing as needed. Educate patients about signs of toxicity (nausea, tachycardia, tremors) and subtherapeutic levels (worsening dyspnea).

Not necessarily. For patients who are clinically stable on theophylline, have good serum level control, and face cost or practical barriers to inhaled therapy, continuing theophylline remains appropriate. Consider transitioning if: the patient has had repeated treatment gaps due to the shortage, would benefit clinically from inhaled therapy, or monitoring burden is a concern.

Prior authorization requirements vary by plan. For tiotropium (Spiriva) and ICS/LABA combinations, most plans do require prior authorization for COPD. Documenting the shortage as the reason for switching, along with a clinical narrative, will strengthen the PA request. Generic montelukast typically has minimal prior auth requirements.

Most transitions can overlap for a brief period to ensure continuity of bronchodilation. Start the new inhaled medication first, allow the patient to adjust over 3–5 days, then discontinue theophylline. Monitor symptom control closely for 2–4 weeks after the transition. Serum monitoring is no longer needed once theophylline is discontinued.

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