Comparative Pharmacology
Head-to-head clinical analysis: QUIBRON T versus QUIBRON T SR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: QUIBRON T versus QUIBRON T SR.
QUIBRON-T vs QUIBRON-T/SR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Quibron-T (theophylline) inhibits phosphodiesterase, increasing intracellular cAMP in airway smooth muscle and inflammatory cells, leading to bronchodilation and anti-inflammatory effects. It also antagonizes adenosine receptors and enhances respiratory drive.
Theophylline is a methylxanthine that relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular cAMP, and antagonizing adenosine receptors.
Oral: 200-400 mg every 6-8 hours; sustained-release: 200-600 mg every 12 hours.
200-400 mg orally every 12 hours; extended-release tablets. Initial dose 200 mg every 12 hours; may increase by 200 mg daily every 3-7 days based on serum theophylline levels (target 5-15 mcg/mL). Maximum 800 mg/day.
None Documented
None Documented
Terminal elimination half-life: 7-9 hours in nonsmoking adults; prolonged in hepatic cirrhosis (up to 30 hours) or heart failure; shorter in smokers (4-5 hours) due to enzyme induction.
Terminal t1/2: 3-12 hours (adults); 1-9 hours (children); prolonged in cirrhosis (up to 30 hours), heart failure, elderly. Clinical context: Narrow therapeutic index (5-15 mcg/mL); dosing interval adjusted based on t1/2.
Renal: 70% as metabolites (1,3-dimethyluric acid, 3-methylxanthine, and 1-methyluric acid) and 10% as unchanged drug in adults; biliary/fecal: minimal, <5%.
Renal: ~10% unchanged; Hepatic metabolism (CYP1A2, CYP3A4): 90% to inactive metabolites (1,3-dimethyluric acid, 3-methylxanthine, 1-methyluric acid). Biliary/fecal: minimal (<5%).
Category C
Category C
Xanthine Bronchodilator
Xanthine Bronchodilator