Comparative Pharmacology
Head-to-head clinical analysis: ELIXOPHYLLIN versus ELIXOPHYLLIN SR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ELIXOPHYLLIN versus ELIXOPHYLLIN SR.
ELIXOPHYLLIN vs ELIXOPHYLLIN SR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Inhibits phosphodiesterase, increasing intracellular cAMP, leading to bronchodilation and anti-inflammatory effects.
Theophylline relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular cAMP, and antagonizing adenosine receptors. It also has anti-inflammatory effects by reducing eosinophil infiltration and cytokine release.
Theophylline (Elixophyllin) immediate-release: Initial dose 300 mg/day PO divided every 6-8 hours; titrate based on serum theophylline concentration (target 5-15 mcg/mL). Typical adult dose 400-600 mg/day PO divided every 6-8 hours. Sustained-release: 400-600 mg/day PO every 12 hours.
300-600 mg orally every 12 hours; extended-release tablets. Adjust based on serum theophylline concentrations (target 5-15 mcg/mL).
None Documented
None Documented
Terminal elimination half-life in adults is approximately 7-9 hours (range 3-12 hours) for non-smokers, and 4-5 hours for smokers. In children (1-9 years), half-life averages 3-4 hours; in neonates, it is prolonged (20-30 hours). Clinical context: Half-life may be increased in hepatic impairment, congestive heart failure, and with concurrent administration of drugs that inhibit CYP1A2 and CYP3A4 (e.g., cimetidine, erythromycin, ciprofloxacin). Decreased half-life occurs with enzyme inducers (e.g., phenytoin, carbamazepine, rifampin, smoking).
Terminal elimination half-life: 7-9 hours in adults (nonsmokers). In smokers, hepatic clearance is increased, reducing half-life to 4-5 hours. In patients with hepatic cirrhosis, half-life may extend to 24 hours. In neonates, half-life is prolonged (20-30 hours).
Theophylline is primarily eliminated by hepatic metabolism (approximately 90%), with less than 10% excreted unchanged in urine. Renal excretion of unchanged drug accounts for about 10% in adults, but in neonates and infants, it may be higher (up to 50%). Fecal excretion is negligible (<1%).
Renal: approximately 90% of the dose is eliminated via hepatic metabolism (N-demethylation and hydroxylation), with about 10% excreted unchanged in urine. The primary metabolites are 1-methylxanthine, 1,3-dimethyluric acid, and 3-methylxanthine. Fecal excretion is negligible (<1%).
Category C
Category C
Xanthine Bronchodilator
Xanthine Bronchodilator