DYPHYLLINE IS A XANTHINE DERIVATIVE WITH PHARMACOLOGIC ACTIONS SIMILAR TO THEOPHYLLINE AND OTHER MEMBERS OF THIS CLASS OF DRUGS. ITS PRIMARY ACTION IS THAT OF BRONCHODILATION, BUT IT ALSO EXHIBITS PERIPHERAL VASODILATORY AND OTHER SMOOTH MUSCLE RELAXANT ACTIVITY TO A LESSER DEGREE. THE BRONCHODILATORY ACTION OF DYPHYLLINE, AS WITH OTHER XANTHINES, IS THOUGHT TO BE MEDIATED THROUGH COMPETITIVE INHIBITION OF PHOSPHODIESTERASE WITH A RESULTING INCREASE IN CYCLIC AMP PRODUCING RELAXATION OF BRONCHIAL SMOOTH MUSCLE.
THE ELIMINATION HALF-LIFE OF DYPHYLLINE IS APPROXIMATELY TWO HOURS. THE RENAL CLEARANCE WOULD BE CORRESPONDINGLY REDUCED IN PATIENTS WITH IMPAIRED RENAL FUNCTION. IN ANURIC PATIENTS, THE HALF-LIFE MAY BE INCREASED 3 TO 4 TIMES NORMAL