Comparative Pharmacology
Head-to-head clinical analysis: SOMOPHYLLIN versus THEO DUR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SOMOPHYLLIN versus THEO DUR.
SOMOPHYLLIN vs THEO-DUR
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 cAMP levels, and antagonizing adenosine receptors. It also has anti-inflammatory and immunomodulatory effects.
Inhibits phosphodiesterase, increasing cAMP levels; antagonizes adenosine receptors; enhances contractility of skeletal and cardiac muscle, and relaxes bronchial smooth muscle.
Oral: 200–400 mg every 6 hours; IV: 6 mg/kg loading dose over 30 minutes, then 0.4–0.6 mg/kg/h continuous infusion.
300-600 mg orally twice daily
None Documented
None Documented
The terminal elimination half-life of theophylline is approximately 8 hours in healthy non-smoking adults (range 3-12 hours). It is prolonged in patients with hepatic cirrhosis (up to 30 hours), heart failure (up to 30 hours), and in neonates (20-30 hours). Smoking (including marijuana) decreases half-life to 4-5 hours. Half-life is shorter in children (3-5 hours). Clinical context: Due to narrow therapeutic index, half-life variability necessitates therapeutic drug monitoring.
Terminal elimination half-life: 3-9 hours in adults (smokers: 4-5 hours; nonsmokers: 6-9 hours); 20-30 hours in premature neonates; 1-5 hours in children. Prolonged in hepatic cirrhosis, heart failure, and with CYP1A2 inhibitors.
Theophylline is primarily eliminated by hepatic metabolism (>90%), with only about 10-15% excreted unchanged in urine. Renal excretion of the parent drug is minor; however, metabolites are excreted renally. Biliary/fecal excretion accounts for less than 1%.
Primarily hepatic metabolism by CYP1A2 and CYP3A4; renal excretion of unchanged drug accounts for approximately 10% in adults, up to 50% in neonates; biliary/fecal excretion negligible.
Category C
Category C
Bronchodilator
Bronchodilator