Comparative Pharmacology
Head-to-head clinical analysis: SOMOPHYLLIN versus XOPENEX HFA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: SOMOPHYLLIN versus XOPENEX HFA.
SOMOPHYLLIN vs XOPENEX HFA
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.
Selective beta-2 adrenergic receptor agonist; relaxes bronchial smooth muscle by increasing intracellular cyclic AMP via activation of adenylyl cyclase.
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.
2 inhalations (90 mcg each) every 4-6 hours as needed via oral inhalation. Maximum 12 inhalations per 24 hours.
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: 3-4 hours; clinical context: dosing every 4-6 hours for bronchodilation
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%.
Renal: 80-100% as unchanged drug and metabolites; fecal: minimal (<5%)
Category C
Category C
Bronchodilator
Bronchodilator