Doxofree Mechanism of Action

Pharmacologic Category: Bronchodilator (Xanthine).
Pharmacology: Pharmacodynamics: Doxofylline is a methylxanthine derivative that possesses potent bronchodilator activity by inhibiting phosphodiesterase enzymes followed by an increase in cyclic-3',5' adenosine monophosphate (cAMP) resulting in smooth muscle relaxation.
Pharmacokinetics: The half-life of Doxofylline is greater than 6 hours; so, this allows effective constant plasma levels with a thrice a day dose regimen. Single dose pharmacokinetics studies in humans after oral administration defined distribution and absorption of the drug.
After administration, peak plasma levels are reached after 1 hour. Absolute bioavailability is about 62.6%; at pH 7.4, plasma proteins binding the compound are about 48%. Less than 4% of an orally administered dose is excreted unchanged in the urine.
Doxofylline is almost completely metabolized in the liver (90% of the total drug clearance). Hydroxy ethyl theophylline is the only detectable circulating metabolite of Doxofylline.
After repeated administration, Doxofylline (Doxofree) reaches the steady state in about 4 days; the elimination half-life during long-term treatment is 8-10 hours: this may decrease the hepatic clearance of xanthines, causing an increase in blood levels. No evidence of a relationship between Doxofylline (Doxofree) serum concentration and toxic events has been reported.