Comparative Pharmacology
Head-to-head clinical analysis: QUIBRON T SR versus SLO PHYLLIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: QUIBRON T SR versus SLO PHYLLIN.
QUIBRON-T/SR vs SLO-PHYLLIN
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.
SLO-PHYLLIN (theophylline) is a xanthine bronchodilator that relaxes bronchial smooth muscle, likely by inhibiting phosphodiesterase, increasing intracellular cAMP, blocking adenosine receptors, and enhancing endogenous catecholamine release.
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.
Theophylline (Slo-Phyllin) immediate-release: 100-200 mg orally every 6 hours; sustained-release: 200-400 mg orally every 12 hours. Dose titrated 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 is approximately 3-8 hours in adults (non-smokers, healthy), 1-5 hours in smokers, and 20-30 hours in neonates. Clinical context: Half-life is prolonged in hepatic cirrhosis, heart failure, and with certain drug interactions (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: ~10% unchanged; hepatic metabolism accounts for ~90% of elimination, with metabolites excreted in urine. Fecal: <5%.
Category C
Category C
Xanthine Bronchodilator
Xanthine Bronchodilator