Theo 24 CR (theophylline anhydrous) 400 mg and 600 mg extended-release tablets are formulated to provide sustained bronchodilation and anti-inflammatory effects for the management of chronic asthma and other reversible airway obstructions, such as chronic obstructive pulmonary disease (COPD). As a methylxanthine derivative, it functions primarily through phosphodiesterase inhibition and adenosine receptor antagonism, resulting in smooth muscle relaxation and improved pulmonary function. Its unique 24-hour controlled-release delivery system ensures stable serum concentrations, minimizing peak-trough fluctuations and supporting consistent therapeutic efficacy. This profile is intended for healthcare professionals managing patients requiring long-term bronchodilator therapy.

Features

• Active ingredient: Theophylline anhydrous
• Available strengths: 400 mg and 600 mg extended-release tablets
• Pharmacologic class: Methylxanthine bronchodilator
• Mechanism: Non-selective phosphodiesterase inhibition, adenosine receptor antagonism
• Delivery system: 24-hour controlled-release matrix for once-daily dosing
• Bioavailability: Approximately 100% under fasting conditions
• Half-life: 6.8–8.8 hours in adult non-smokers; highly variable based on age, comorbidities, and concomitant medications
• Protein binding: 40%, primarily to albumin
• Metabolism: Hepatic, via cytochrome P450 1A2 (CYP1A2)
• Excretion: Renal (10% unchanged, 90% metabolites)

Benefits

• Provides round-the-clock bronchodilation, reducing frequency and severity of bronchospastic episodes
• Sustained therapeutic serum levels help prevent nocturnal asthma symptoms and morning dips in lung function
• Once-daily dosing improves adherence compared to shorter-acting bronchodilators
• May reduce dependence on short-acting beta-agonists for rescue therapy
• Offers anti-inflammatory effects that may contribute to long-term airway remodeling control
• Suitable for patients who are poorly responsive or intolerant to inhaled corticosteroids or beta-agonists

Common use

Theo 24 CR is indicated for the symptomatic treatment and chronic management of bronchospasm associated with asthma, chronic bronchitis, emphysema, and other COPD variants. It is typically prescribed when long-acting bronchodilation is required and may be used as monotherapy or as part of a combination regimen with inhaled corticosteroids, especially in moderate to severe persistent asthma. It is also utilized in cases where patients exhibit poor technique or adherence with inhaled medications, or when cost is a consideration.

Dosage and direction

Dosage must be individualized based on ideal body weight, age, smoking status, and concomitant factors affecting theophylline metabolism. Initiate therapy at 400 mg once daily in adults, preferably taken in the morning with a full glass of water on an empty stomach (1 hour before or 2 hours after a meal). Dosage may be titrated in increments of 100–200 mg every 3 days to a maximum of 600 mg daily, if tolerated and based on serum theophylline levels. Therapeutic range is 10–20 mcg/mL; levels should be monitored after 3 days of a new dose, then periodically. Do not crush, chew, or break tablets.

Precautions

Use with caution in patients with cardiac arrhythmias, congestive heart failure, cor pulmonale, hepatic impairment, hyperthyroidism, history of peptic ulcer, or seizure disorders. Elderly patients, neonates, and those with acute febrile illnesses may exhibit reduced clearance. Avoid abrupt withdrawal. Monitor for signs of toxicity, especially during dosage adjustments or introduction of drugs that inhibit CYP1A2. Use during pregnancy only if clearly needed (Category C). Theophylline is excreted in breast milk and may cause irritability in infants.

Contraindications

Hypersensitivity to theophylline or any component of the formulation. Contraindicated in patients with active peptic ulcer disease or uncontrolled seizure disorders. Not recommended in individuals with known hypersensitivity to xanthine derivatives.

Possible side effect

Common: Nausea, vomiting, headache, insomnia, gastroesophageal reflux, tremor, palpitations.
Less common: Tachycardia, PVCs, hypotension, hyperglycemia, hypokalemia, diuresis.
Rare but serious: Ventricular arrhythmias, seizures, life-threatening toxicity (usually at serum levels >30 mcg/mL).

Drug interaction

• CYP1A2 inhibitors: Cimetidine, fluvoxamine, certain fluoroquinolones, zileuton → increased theophylline levels
• CYP1A2 inducers: Smoking, phenobarbital, rifampin → decreased theophylline levels
• Drugs that lower seizure threshold: May synergize with theophylline
• Beta-blockers: May antagonize bronchodilator effects
• Lithium: Theophylline may increase renal lithium excretion

Missed dose

If a dose is missed, take it as soon as remembered unless it is nearly time for the next dose. Do not double the dose. Maintaining consistent timing is critical to avoiding serum concentration fluctuations.

Overdose

Symptoms include severe nausea/vomiting, agitation, tachycardia, arrhythmias, hyperglycemia, hypokalemia, seizures, and metabolic acidosis. Serum levels >30 mcg/mL are associated with life-threatening toxicity. Treatment includes activated charcoal (if recent ingestion), supportive care, IV benzodiazepines for seizures, and—in severe cases—hemodialysis.

Storage

Store at 20–25°C (68–77°F). Keep in a tightly closed container away from moisture, light, and excessive heat. Keep out of reach of children.

Disclaimer

This information is intended for healthcare professionals and should not replace clinical judgment. Always verify dosing and monitor serum theophylline levels during therapy. Patients should be educated on signs of toxicity and the importance of adherence and follow-up.

Reviews

Clinical studies and post-marketing surveillance indicate that Theo 24 CR is effective in maintaining therapeutic theophylline levels with once-daily dosing. It is generally well-tolerated when serum concentrations are kept within the therapeutic window. Healthcare providers appreciate the adherence benefits, though many emphasize the necessity of therapeutic drug monitoring. Some patients report improved nighttime symptoms and reduced rescue inhaler use.