Comparative Pharmacology
Head-to-head clinical analysis: QUIBRON T SR versus SLO BID.
Peer-Reviewed Evidence
Head-to-head clinical analysis: QUIBRON T SR versus SLO BID.
QUIBRON-T/SR vs SLO-BID
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Theophylline is a methylxanthine that relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular cAMP, and antagonizing adenosine receptors.
Relaxes smooth muscle of bronchial airways and pulmonary blood vessels by inhibiting phosphodiesterase, increasing intracellular cAMP, and promoting bronchodilation.
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.
Dose: 300-600 mg orally every 12 hours. Immediate-release: 5 mg/kg loading dose then 3 mg/kg every 6 hours. Extended-release: 10-15 mg/kg/day divided every 12 hours. Titrate to serum theophylline concentration of 5-15 mcg/mL.
None Documented
None Documented
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.
Terminal elimination half-life: 3-15 hours (mean ~10 hours in adults; 20-30 hours in neonates; 1-5 hours in smokers). Clinically, half-life decreases with smoking, increases with hepatic disease, heart failure, and certain drugs (e.g., cimetidine, ciprofloxacin).
Renal: ~10% unchanged; Hepatic metabolism (CYP1A2, CYP3A4): 90% to inactive metabolites (1,3-dimethyluric acid, 3-methylxanthine, 1-methyluric acid). Biliary/fecal: minimal (<5%).
Renal: 90% as metabolites (caffeine, theobromine, paraxanthine, and unchanged drug; 1,3-dimethyluric acid, 1-methyluric acid, and 3-methylxanthine). Biliary/fecal: <10%.
Category C
Category C
Xanthine Bronchodilator
Xanthine Bronchodilator