Addiction to Caffeine and Other Xanthines

Abstract

Xanthine (3,7-dihydro-purine-2,6-dione) is a purine base that can naturally be found in human body tissues and fluids as well as in plants and other organisms. Methylated xanthines (methylxanthines) are phosphodiesterase inhibitors and adenosine receptor antagonists. Methylxanthines have thus different effects: reduce inflammation and immunity, reduce sleepiness, and increase alertness, but also stimulate the heart rate and contraction and dilate the bronchi. The most well-known methylxanthines are caffeine, methylbromine, and theophylline. Large observational studies suggest that caffeine may have long-term health benefits. Coffee and caffeine withdrawal symptoms exist and are often not recognized, especially in treatment settings, where caffeine withdrawal can be confounded with other symptoms. Caffeine intoxication and withdrawal are recognized clinical entities, but caffeine dependence is currently not. Caffeine withdrawal symptoms occur in half of regular coffee drinkers, even at moderate caffeine intake. The most common symptoms are headache, fatigue, and difficulty to concentrate. Health professionals and patients should be better informed about these symptoms and the risk of occurrence of caffeine withdrawal. There is little research on treatments for clinical problems associated with xanthine use or abuse.