QUIBRON-T/SR 300 MG (THEOPHYLLINE ANHYDROUS) – DIVIDOSE SUSTAINED-RELEASE TABLETS

Quibron-T/SR 300 mg contains Theophylline Anhydrous 300 mg, a bronchodilator belonging to the methylxanthine class of medicines.

It features a sustained-release Dividose formulation designed to provide prolonged theophylline release, helping relax bronchial smooth muscles, widen the airways, and improve airflow in patients with certain respiratory conditions.

Pack size: 100 tablets.

Composition

• Active ingredient: Theophylline Anhydrous 300 mg.
• Pharmaceutical class: Methylxanthine bronchodilator.
• Dosage form: Dividose sustained-release oral tablets.
• Pack size: 100 tablets.

Mechanism of Action

Theophylline works through several mechanisms:

• Inhibits phosphodiesterase enzymes (mainly PDE III and PDE IV), helping relax bronchial smooth muscles.
• Produces bronchodilation, facilitating airflow through the respiratory passages.
• Helps suppress airway responses to certain stimuli.
• Enhances the contractile strength of the diaphragm, supporting respiratory muscle function.

Indications

Quibron-T/SR may be prescribed for the management of:

• Bronchial asthma: Long-term management of symptoms associated with reversible airway obstruction.
• Chronic bronchitis: Relief of bronchospasm associated with chronic airway inflammation.
• Pulmonary emphysema: Management of respiratory symptoms associated with airflow obstruction.
• Other chronic obstructive respiratory conditions: When theophylline is considered appropriate by the treating physician.

Important: It is intended for maintenance treatment and is not suitable for immediate relief of an acute asthma attack.

Benefits / Therapeutic Effects

• Helps relax bronchial smooth muscles and widen the airways.
• Supports improved airflow and respiratory function.
• Helps reduce symptoms associated with reversible bronchial obstruction.
• Supports respiratory muscle function by enhancing diaphragmatic contractility.
• Sustained-release formulation provides prolonged drug delivery.

Dosage & Administration

• Adults: Dosage should be individualized according to body weight, clinical response, tolerability, and serum theophylline concentrations.
• Treatment is generally initiated at a relatively low dose and gradually adjusted under medical supervision.
• The sustained-release formulation may allow administration at approximately 12-hour intervals in many patients, depending on the prescribed regimen.
• Take orally as directed by the physician.
• Swallow tablets according to the product instructions; do not crush or chew sustained-release tablets.
• The Dividose formulation is designed to allow dose adjustments through tablet division; divide only as instructed by the product leaflet or healthcare professional.

Important: A 300 mg tablet is not automatically intended to be taken twice daily. Theophylline has a narrow therapeutic index, making individualized dosing and blood-level monitoring essential.

Possible Side Effects

Commonly reported side effects include:

• Nausea and vomiting.
• Headache.
• Insomnia and sleep disturbances.
• Restlessness and nervousness.
• Tremors.
• Palpitations and increased heart rate.
• Diarrhea.
• Irritability.

Potential signs of theophylline toxicity:

• Persistent or severe vomiting.
• Significant cardiac arrhythmias.
• Severe agitation or confusion.
• Seizures.

These symptoms require prompt medical evaluation, particularly when toxicity is suspected.

Contraindications & Precautions

• Hypersensitivity to theophylline or any of the product's ingredients.
• Use with extreme caution in patients with:
  • Active peptic ulcer disease.
  • Seizure disorders or epilepsy.
  • Cardiac arrhythmias.
  • Liver impairment.
  • Congestive heart failure.
  • Hyperthyroidism.
• Elderly patients may require lower doses and more frequent monitoring.
• Smoking and smoking cessation can significantly alter theophylline blood concentrations.
• Persistent fever and acute infections may reduce theophylline clearance and increase the risk of toxicity.
• Pregnancy and breastfeeding require medical assessment before use.

Drug Interactions

Several medications can significantly affect theophylline blood concentrations.

Medications that may increase theophylline concentrations:

• Cimetidine.
• Erythromycin.
• Clarithromycin.
• Ciprofloxacin.
• Allopurinol (particularly at higher doses).
• Fluvoxamine.

Medications that may decrease theophylline concentrations:

• Carbamazepine.
• Rifampicin.
• Aminoglutethimide.

Patients should inform their healthcare provider about all medications they are taking before starting treatment.

Monitoring

• Monitor serum theophylline concentrations to ensure therapeutic effectiveness and minimize toxicity.
• Monitor heart rate and cardiac rhythm when clinically indicated.
• Assess for gastrointestinal and neurological adverse effects.
• Reassess theophylline levels following dose adjustments, changes in smoking habits, persistent fever, or the introduction or discontinuation of interacting medications.

Storage

• Store according to the manufacturer's recommended storage conditions.
• Keep in a dry place, away from excessive heat and moisture.
• Keep out of reach of children.

References

1. Quibron-T/SR Official Prescribing Information: Product composition, mechanism of action, indications, contraindications, dosage, and safety information.
2. U.S. National Library of Medicine – DailyMed: Theophylline Extended-Release Tablets, official drug labeling and pharmacological information.
3. Global Initiative for Asthma (GINA): Global Strategy for Asthma Management and Prevention, 2026.
4. U.S. Food and Drug Administration (FDA): Theophylline extended-release prescribing information and therapeutic drug monitoring recommendations.

Patient Disclaimer:

This information is provided for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Quibron-T/SR is a prescription medication and should only be used under medical supervision. Do not start, discontinue, or adjust the dose without consulting your healthcare professional. Theophylline has a narrow therapeutic index, and inappropriate dosing may lead to serious or potentially life-threatening toxicity.