AMINOPHYLLINE AND RELATED XANTHINE DERIVATIVES

The methyl derivatives of xanthine for which therapeutic claims have been made include caffeine, theobromine and theophylline. The slight solubility of the latter two limits their usefulness, but soluble double salts of either theobromine or theophylline can be formed with a number of compounds. The most widely used combinations are theobromine calcium salicylate or sodium acetate and theophylline ethylenediamine (aminophylline). Caffeine, although the first of the xanthines to be studied and used, has in recent years succumbed to the greater interest shown in theobromine and theophylline. The stimulating effects of caffeine on the central nervous system are somewhat greater than shown by theobromine and theophylline, and its effects on the circulation are definitely less. Theophylline may also produce stimulation of the central nervous system. In addition, the latter drug has the disadvantage of causing gastric and occasionally renal irritation. DIURETIC ACTION The value of the xanthines as diuretics dates back