methylxanthine
2 interactions related to methylxanthine
caffeine + theophylline
Caffeine and theophylline are closely related methylxanthines that share the CYP1A2 metabolic pathway and compete for the same adenosine receptors. Concurrent use can raise theophylline levels and add pharmacodynamically to cause tachycardia, tremor, nausea, seizures or arrhythmias.
caffeinetheophyllinemethylxanthineasthmacopdcyp1a2narrow therapeutic indextoxicity
chocolate + adenosine
Caffeine and theobromine from chocolate are competitive antagonists at A1 and A2A adenosine receptors. When intravenous adenosine is used for cardiac stress testing or to terminate supraventricular tachycardia, recent methylxanthine intake can blunt its effects and lead to a falsely negative test or failure to convert the arrhythmia.
chocolateadenosineregadenosoncardiac stress testcaffeinetheobrominemethylxanthineSVTnuclear stress test