indication

For relief of acute bronchial asthma and for reversible bronchospasm associated with chronic bronchitis and emphysema.

pharmacology

Dyphylline, a xanthine derivative, is a bronchodilator used for relief of acute bronchial asthma and for reversible bronchospasm associated with chronic bronchitis and emphysema. 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.

mechanism of action

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 as well as antagonism of adenosine receptors.

toxicity

LD₅₀=1954 mg/kg (orally in mice)

biotransformation

Hepatic

half life

2 hours (range 1.8 - 2.1 hours)

route of elimination

Dyphylline exerts its bronchodilatory effects directly and, unlike the­ophylline, is excreted unchanged by the kidneys without being metabolized by the liver. Approximately 88% of a single oral dose can be recovered from the urine unchanged.

drug interactions

Aciclovir: Acyclovir increases the effect and toxicity of dyphylline.

Adenosine: This xanthine decreases the effect of adenosine

Bromazepam: Dyphylline may decrease the therapeutic effect of bromazepam. Monitor for changes in the therapeutic effects of bromazepam if dyphylline is initiated, discontinued or dose changed.

Carbamazepine: Carbamazepine may decrease the serum concentration of diphylline. Diphylline may decrease the serum concentration of carbamazepine. Monitor for changes in the therapeutic effect of both agents if concomitant therapy is initiated, discontinued or dose changed.

Cimetidine: Increases the effect of theophylline

Ciprofloxacin: Ciprofloxacin may increase the effect of dyphylline.

Clarithromycin: Increases the effect and toxicity of theophylline

Disulfiram: Increases the effect and toxicity of theophylline

Erythromycin: The macrolide, erythromycin, may increase the effect and toxicity of the theophylline derivative, dyphylline.

Ethinyl Estradiol: The contraceptive increases the effect and toxicity of theophylline

Fluvoxamine: Increases the effect and toxicity of theophylline

Fosphenytoin: Decreased effect of both products

Grepafloxacin: Grepafloxacin may increase the effect of dyphylline.

Interferon Alfa-2a, Recombinant: Interferon increases the effect and toxicity of theophylline

Interferon Alfa-2b, Recombinant: Interferon increases the effect and toxicity of theophylline

Interferon alfa-n1: Interferon increases the effect and toxicity of theophylline

Isoniazid: Increases the effect and toxicity of theophylline

Lithium: Theophylline decreases serum levels of lithium

Mexiletine: Mexiletine increases the effect and toxicity of theophylline

Nadolol: Antagonism of action and increased effect of theophylline

Norfloxacin: Norfloxacin may increase the effect of dyphylline.

Peginterferon alfa-2a: Interferon increases the effect and toxicity of theophylline

Peginterferon alfa-2b: Interferon increases the effect and toxicity of theophylline

Pentoxifylline: Pentoxifylline increases the effect and toxicity of theophylline

Phenobarbital: The barbiturate, phenobarbital, decreases the effect of dyphylline.

Phenytoin: Decreased effect of both products

Pindolol: Antagonism of action and increased effect of theophylline

Primidone: The barbiturate, primidone, decreases the effect of dyphylline.

Propafenone: Propafenone increases the effect of theophylline

Propranolol: Antagonism of action and increased effect of theophylline

Rifampin: Rifampin decreases the effect of theophylline

Temazepam: Dyphylline may decrease the efficacy of Temazepam. Monitor for changes in the therapeutic effect of Temazepam if Dyphylline is initiated, discontinued or dose changed.

Terbinafine: Terbinafine increases the effect and toxicity of theophylline

Ticlopidine: Ticlopidine increases the effect and toxicity of theophylline

Timolol: Antagonism of action and increased effect of theophylline