No evidence of a relationship between doxofylline serum conc and toxic events has been reported with potential drug interreactions.

Doxyfylline reacts with broad variety of drugs that alter the rate of theophylline clearance leading to incr or decr of serum theophylline conc.

Because of narrow therapeutic index, serum theophylline conc need to be monitored. Conversely because of a wider therapeutic window there is no need to monitor doxofylline levels

U.S FDA APPROVED DRUGS FROM 01-01-08 TO 31-12-08

Nausea, vomiting, epigastric pain, headache, irritability, insomnia, tachycardia, extrasystole, occasionally hyperglycemia, and albuminuria may occur

Hypersensitivity to its components, acute myocardial infraction, hypotension, and in lactating women.

Precuations-

Doxyfylline should be given to pregnant women, if clearly needed as limited data is for use in humans during pregnancy.

Doxofylline must be used with caution in patients with hypertension, heart disease, hyperthyroidism, chronic right vetricular disaease, congestive heart failure, liver diseases, renal diseases, in those with a history of peptic ulcer, and in the elderly.

Severe arrhythmias and seizure could be the first signs of potential overdose

Plasma conc in doxofylline should be monitored in patients with liver disease, congestive heart failure and concomittant intake of certain drugs ( erythromycin, troleandromycin, lincomycin, allopurinol, cimetidine, propranol, and antiflu vaccine. In these cases a lower dose of doxofylline is needed

Phenytoin, other anticonvulsants and smoking may cause an increase in clearance with a shorter mean half life. In these cases higher doses of doxyfylline may be required.

Date of approval     2006

Bronchial asthma, COPD

Dosage-

400mg twice daily, dosage may be increased to thrice daily according to prescribing physician

Children- prescriberd dose is 12mg/kg divided into 2 doses into 2 doses.

Elderly- Dosage may be reduced to half tablet twice a day.

Pharmacology

Doxofylline ( 7-(1-, 3 -dioxoln -2-ylmethy ) theophylline is a novel methylxanthine bronchodilator characterised by the presence of a dioxolane group in position 7, which differentiates it from theophylline. Doxofylline acts by inhibiting the phosphodiesetrase enzymes in central and peripheral tissues. The increases intracellular concentration of cyclic AMP that causes smooth muscle relaxation. Doxfylline has shown more potent and bronchospastic activity and less extra respiratory effects in experimental studies than commonly used xanthine drugs.

Pharmacokinetics

Half life of doxofylline is greater than six hours which allows effective constant plasma levels with thrice daily dose regimen. The therapeutic range of doxofylline is significantly wider with respect to that of theophylline. Serum levels are stable and do not require monitoring.

Pregnancy

Doxyfylline should be given to pregnant women, if clearly needed as limited data is for use in humans during pregnancy.