Theo 24 CR (Theophylline Extended-Release Tablets, 24 Hour) is a prescription bronchodilator meticulously engineered to provide sustained, around-the-clock relief for chronic respiratory conditions. As a methylxanthine derivative, it functions by relaxing the smooth muscles of the bronchial airways and pulmonary blood vessels, thereby improving breathing capacity and reducing the frequency of exacerbations. Its unique 24-hour controlled-release delivery system ensures stable serum theophylline levels, minimizing peak-trough fluctuations and supporting consistent symptom management. This formulation is specifically indicated for the treatment and prevention of symptoms from asthma, chronic bronchitis, emphysema, and other chronic obstructive pulmonary diseases (COPD), making it a cornerstone in long-term maintenance therapy for patients requiring continuous pharmacological support.

Features

• 24-hour controlled-release theophylline formulation for once-daily dosing convenience
• Available in multiple strengths (e.g., 100 mg, 200 mg, 300 mg, 400 mg) to allow for precise therapeutic individualization
• Hydrophilic matrix system designed for gradual, predictable drug release
• Formulated to minimize the risk of dose dumping and reduce peak-to-trough variability
• Bioequivalent to other extended-release theophylline products with established pharmacokinetic profile

Benefits

• Provides continuous, 24-hour bronchodilation, reducing the frequency of daytime and nocturnal respiratory symptoms
• Decreases the occurrence of acute asthma attacks and COPD exacerbations, potentially reducing emergency department visits
• Improves overall lung function parameters, including forced expiratory volume (FEV1) and peak expiratory flow rate (PEFR)
• Enhances exercise tolerance and quality of life by maintaining open airways during physical activity
• Supports adherence through simplified once-daily dosing, minimizing the burden of complex medication schedules
• Offers a non-steroidal option for long-term control, which may be suitable for patients who cannot tolerate or have contraindications to inhaled corticosteroids

Common use

Theo 24 CR is primarily prescribed for the long-term management of chronic respiratory disorders characterized by reversible airway obstruction. Its most frequent applications include the maintenance treatment of bronchial asthma, where it helps prevent wheezing, shortness of breath, and chest tightness. It is also widely used in the management of chronic bronchitis and emphysema—key components of COPD—to alleviate persistent coughing, dyspnea, and sputum production. Clinicians may employ it as monotherapy or as part of a combination regimen with inhaled corticosteroids or long-acting beta-agonists, depending on disease severity and patient-specific factors. Its around-the-clock action is particularly beneficial for patients who experience nighttime or early morning symptoms, providing therapeutic coverage during these vulnerable periods.

Dosage and direction

Dosage of Theo 24 CR must be highly individualized based on age, weight, smoking status, concurrent illnesses, and other factors affecting theophylline metabolism. The objective is to achieve and maintain a steady-state serum theophylline concentration within the therapeutic range of 10–20 mcg/mL.

Initial Dosing: For adults and children over 12 years old who are non-smokers and without complicating factors, the typical starting dose is 300–400 mg once daily. For older patients, those with cor pulmonale, cardiac failure, or liver dysfunction, the initial dose should not exceed 200 mg once daily. Dosage may be increased in increments of no more than 100 mg every 3 days until the desired clinical response is achieved or the maximum recommended dose is reached.

Maintenance Dosing: The average maintenance dose for adults is 400–600 mg daily, though some patients may require up to 900 mg/day. Doses exceeding 600 mg/day should be administered in divided doses (e.g., 400 mg in the morning and 200–400 mg in the evening) to minimize concentration-dependent side effects.

Administration: Tablets must be swallowed whole and must not be chewed, crushed, or divided. They should be taken at the same time each day, preferably in the evening, to ensure optimal overnight coverage. Administration with a high-fat meal may increase the rate and extent of absorption; therefore, consistency in timing relative to meals is advised.

Monitoring: Serum theophylline concentrations should be monitored after initiation, after each dosage adjustment, and periodically during long-term therapy (e.g., every 6–12 months). Trough levels are typically measured just before the next dose.

Precautions

Theophylline has a narrow therapeutic index and requires careful clinical oversight. Several factors can significantly alter its clearance and predispose patients to toxicity:

• Hepatic impairment: Patients with liver disease, cirrhosis, or acute hepatitis may have markedly reduced clearance. Dose reductions of 25–50% are often necessary.
• Cardiac failure: Congestive heart failure and cor pulmonale can decrease theophylline clearance. These patients require lower doses and more frequent monitoring.
• Fever: Sustained fever (≥102°F for ≥24 hours) can reduce clearance, particularly in children.
• Elderly patients: Age-related declines in liver function and lean body mass increase the risk of accumulation; conservative dosing is advised.
• Smoking and diet: Tobacco and marijuana smoking induce hepatic enzymes and increase clearance, often requiring higher doses. High-protein, low-carbohydrate diets may reduce clearance, while charcoal-broiled foods can increase it.
• Other conditions: Hypothyroidism, pneumonia, and vaccination with live viruses may reduce clearance.

Patients should be advised to avoid or limit caffeine intake, as it may potentiate theophylline’s adverse effects.

Contraindications

Theo 24 CR is contraindicated in individuals with:

• Hypersensitivity to theophylline or any component of the formulation
• History of theophylline toxicity
• Active peptic ulcer disease
• Uncontrolled seizure disorders (unless receiving adequate anticonvulsant therapy)
• It should not be used concurrently with other xanthine derivatives (e.g., caffeine, pentoxifylline)

Possible side effect

Theophylline side effects are often concentration-dependent and may include:

Common (dose-related):

• Nausea, vomiting, diarrhea, epigastric pain
• Headache, insomnia, restlessness, irritability
• Tachycardia, palpitations

Less common (often at higher concentrations):

• Hyperglycemia
• Hypokalemia
• Increased diuresis
• Fine muscle tremors

Serious (usually at serum concentrations >30 mcg/mL):

• Cardiac arrhythmias (including multifocal atrial tachycardia, ventricular arrhythmias)
• Seizures (may occur without preceding mild symptoms)
• Intractable vomiting leading to metabolic disturbances

Drug interaction

Theophylline interacts with numerous medications that inhibit or induce cytochrome P450 enzymes (primarily CYP1A2 and CYP3A4):

Increased theophylline levels (inhibitors):

• Cimetidine, ciprofloxacin, erythromycin, clarithromycin
• Allopurinol (high dose), fluvoxamine, zileuton
• Oral contraceptives, disulfiram, interferon

Decreased theophylline levels (inducers):

• Phenytoin, carbamazepine, phenobarbital, rifampin
• Smoking (tobacco or marijuana)
• St. John’s Wort

Pharmacodynamic interactions:

• Sympathomimetics: May increase cardiovascular stimulant effects
• Halothane: May predispose to cardiac arrhythmias
• Lithium: Theophylline may increase lithium excretion
• Beta-blockers: May antagonize bronchodilator effects

Missed dose

If a dose is missed, it should be taken as soon as possible on the same day. However, if it is near the time of the next dose, the missed dose should be skipped and the regular dosing schedule resumed. Doubling the dose to compensate for a missed dose is not recommended, as it may lead to toxic serum concentrations.

Overdose

Theophylline overdose is a medical emergency that can be fatal. Signs and symptoms may include severe nausea/vomiting, hematemesis, tremors, hyperthermia, hypotension, cardiac arrhythmias, seizures, and metabolic acidosis. Serum concentrations >30 mcg/mL are associated with major toxicity.

Management:

• Immediate gastric lavage or activated charcoal (even if delayed) to prevent continued absorption
• Multiple-dose activated charcoal and whole bowel irrigation may be considered
• Hemodialysis or charcoal hemoperfusion is highly effective and indicated for serum concentrations >100 mcg/mL in acute overdose or >60 mcg/mL in chronic overdose, or in patients with life-threatening symptoms
• Symptomatic and supportive care, including anticonvulsants for seizures, antiemetics, and electrolyte replacement

Storage

Store at controlled room temperature (20–25°C or 68–77°F). Protect from moisture and light. Keep in the original container, tightly closed. Do not remove desiccant if present. Keep out of reach of children and pets. Do not use beyond the expiration date printed on the packaging.

Disclaimer

This information is intended for educational purposes and does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before starting, changing, or stopping any medication. Dosage and suitability must be determined by a physician based on individual patient characteristics. Never disregard professional medical advice or delay seeking it because of something you have read in this document.

Reviews

Clinical studies and patient reports consistently highlight the efficacy of Theo 24 CR in maintaining bronchial patency over a full 24-hour period. In comparative trials, it has demonstrated non-inferiority to twice-daily theophylline formulations with the advantage of improved adherence. Patients frequently report reduced nighttime awakenings and improved ability to perform daily activities. However, the need for therapeutic drug monitoring is noted as a drawback by some. Overall, it remains a valuable option in the stepwise management of moderate to severe obstructive airway diseases, particularly when other controllers are insufficient or poorly tolerated.