Acefylline (Theophyllineacetic acid), a xanthine derivative, is an Adenosine Receptor antagonist. Acefylline is a peptidylarginine deiminase (PAD) activator. Acefylline is also a bronchodilator and cardiac stimulant that inhibits rat lung cAMP phosphodiesterase isoenzymes. Acefylline can be used in asthma research[1][2][3].