caffeine, theophylline and tannin

Last reviewed 09/2022

Caffeine, theophylline and tannin act as stimulants by inhibiting xanthine oxidase, an enzyme which removes cyclic AMP, the mediator of adrenaline and its analogues. Some people are particularly sensitive to these stimulants and others consume surprisingly large amounts of tea, coffee, chocolate, cola, lager or red wine and yet fail to recognise the link to their symptoms. It is therefore worth asking about consumption of these drinks when patients complain of symptoms possibly due to increased effects of adrenaline.