Theo 24 CR (Theophylline Extended-Release Tablets, 24 Hour) is a methylxanthine bronchodilator indicated for the treatment and prevention of symptoms from asthma, chronic bronchitis, emphysema, and other chronic obstructive pulmonary diseases (COPD). Its unique 24-hour controlled-release delivery system is engineered to maintain consistent serum theophylline concentrations, thereby minimizing peak-trough fluctuations and providing round-the-clock therapeutic coverage. This formulation is designed to improve pulmonary function, reduce the frequency and severity of bronchospastic episodes, and enhance overall quality of life for patients with reversible airway obstruction. Proper therapeutic drug monitoring is essential to maximize efficacy and minimize the risk of adverse events.

Features

• Active ingredient: Theophylline anhydrous
• Dosage form: Extended-release tablets for oral administration
• Available strengths: 100 mg, 200 mg, 300 mg, 400 mg
• Pharmacokinetic profile: Zero-order release over 24 hours
• Mechanism: Non-selective phosphodiesterase inhibition, adenosine receptor antagonism, and histone deacetylase activation
• Bioavailability: Approximately 100% under fasting conditions
• Half-life: Highly variable among individuals (3–15 hours in adults; influenced by age, disease state, concomitant medications)
• Protein binding: 40%, primarily to albumin
• Metabolism: Hepatic, via cytochrome P450 1A2 (CYP1A2)
• Excretion: Renal (10% unchanged theophylline; rest as metabolites)

Benefits

• Provides sustained 24-hour bronchodilation, reducing nocturnal symptoms and morning dips in lung function
• Decreases the frequency and severity of acute exacerbations in chronic asthma and COPD
• May reduce the requirement for short-acting beta-agonists (rescue inhalers)
• Can be used as monotherapy or as an adjunctive agent in a comprehensive respiratory management plan
• Improves exercise tolerance and overall functional capacity in patients with obstructive airway disease
• Cost-effective long-term management option compared to some newer biologic therapies

Common use

Theo 24 CR is commonly prescribed for the maintenance treatment of symptoms associated with chronic asthma and reversible bronchospasm related to chronic bronchitis and emphysema. It is particularly beneficial for patients who experience nocturnal asthma symptoms, as the 24-hour coverage helps prevent overnight bronchoconstriction. Clinicians may also use it as an add-on therapy when inhaled corticosteroids and long-acting beta-agonists do not provide sufficient control. It is not indicated for the relief of acute bronchospasm.

Dosage and direction

Dosage must be individualized based on ideal body weight, age, concomitant illnesses, and potential drug interactions. The recommended starting dose for adults is 300–400 mg once daily, preferably taken in the morning on an empty stomach (at least 1 hour before or 2 hours after a meal). Dosage may be increased in increments of 100–200 mg every 3 days to a maximum of 600 mg daily if tolerated and if serum concentrations indicate subtherapeutic levels. The therapeutic serum concentration range is 10–20 mcg/mL. Serum theophylline levels should be monitored after initiation, after dosage changes, and periodically during long-term therapy. Tablets must be swallowed whole and never crushed, chewed, or broken.

Precautions

Use with caution in patients with congestive heart failure, cor pulmonale, hepatic impairment, alcoholism, or in the elderly due to reduced theophylline clearance. Fever, prolonged hypoxia, and certain viral infections may also alter pharmacokinetics. Smoking (tobacco or marijuana) can increase theophylline metabolism, necessitating higher doses. Conversely, cessation of smoking may lead to toxicity if the dose is not adjusted. Electrolyte imbalances (especially hypokalemia) may potentiate arrhythmogenic effects. Use cautiously in patients with history of seizures or peptic ulcer disease. Regular monitoring of serum concentrations is mandatory to avoid toxicity.

Contraindications

Theo 24 CR is contraindicated in individuals with known hypersensitivity to theophylline or any component of the formulation. It should not be used in patients with active peptic ulcer disease or uncontrolled seizure disorders. Concurrent use with other xanthine derivatives is contraindicated. It is also contraindicated in those with certain cardiac arrhythmias (particularly tachyarrhythmias) not controlled by medication.

Possible side effects

Common adverse reactions (>10%) include nausea, vomiting, headache, insomnia, and gastroesophageal reflux. Less frequently (1–10%), patients may experience nervousness, restlessness, irritability, tachycardia, or increased urination. Serious side effects requiring immediate medical attention include persistent vomiting, cardiac arrhythmias (e.g., atrial fibrillation, ventricular tachycardia), seizures, or signs of hypersensitivity reactions. Toxicity is often concentration-dependent and may occur even within the therapeutic range in susceptible individuals.

Drug interaction

Theophylline interacts with numerous medications. CYP1A2 inhibitors (e.g., cimetidine, ciprofloxacin, fluvoxamine, oral contraceptives, zileuton) can increase serum levels and risk of toxicity. Inducers of CYP1A2 (e.g., phenytoin, carbamazepine, rifampin, smoking) can decrease levels and reduce efficacy. Concurrent use with other sympathomimetic agents may exacerbate cardiovascular effects. Theophylline may antagonize non-depolarizing neuromuscular blocking agents and lithium, and may increase the risk of hypokalemia with diuretics. Always review full medication profile before prescribing.

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 is not recommended due to the risk of toxicity.

Overdose

Theophylline overdose is a medical emergency that may manifest as severe nausea/vomiting, hematemesis, tremors, hyperactivity, cardiac arrhythmias, hypotension, seizures, metabolic acidosis, hypokalemia, hyperglycemia, and potentially death. Serum concentrations >30 mcg/mL are associated with major toxicity. Treatment includes immediate discontinuation, supportive care, activated charcoal (if ingestion recent), and in severe cases, hemodialysis or hemoperfusion. Beta-blockers may be used for tachyarrhythmias but are contraindicated in patients with bronchospasm.

Storage

Store at controlled room temperature (20–25°C or 68–77°F) in a tightly closed container. Protect from moisture and light. Keep out of reach of children and pets. Do not use if the packaging is compromised or if tablets are broken or crushed.

Disclaimer

This information is intended for healthcare professionals and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or medication. Never disregard professional medical advice or delay in seeking it because of something you have read herein. Dosage and administration must be determined by a qualified practitioner based on individual patient factors.

Reviews

Clinical studies and meta-analyses have demonstrated the efficacy of sustained-release theophylline in improving FEV1, reducing symptom scores, and decreasing rescue medication use in patients with persistent asthma and COPD. Many pulmonologists regard it as a valuable third-line or add-on therapy, particularly in resource-limited settings or for specific phenotypes (e.g., nocturnal asthma). However, its narrow therapeutic index and interaction potential require careful management. Patient satisfaction is often high when serum levels are maintained within the therapeutic window without adverse effects, though gastrointestinal side effects remain a common reason for discontinuation.