The pharmaceuticals at issue are the inhibiting proton pump calls of the (IPP), which includes omeprazole, lansoprazole, pantoprazole, esomeprazole and rabeprazole.  These drugs are used for the treatment of the gastric acidity and other related diseases, like the gastro-esophagus reflow, gastric ulcer and duodenal ulcer.

In most reports a latency period that oscillated in several weeks to several months -after the beginning of the treatment with this type of medicines- was demonstrated.  All reports pointed to the disorder in men.

Additionally, The Pharmacovigilance Centre received several reports -concerning these drugs- on impotence, erectile dysfunction and reduction in sexual drive, also related was a reduction in the testosterone levels.

The majority of reports were associated to the use of omeprazole, which agrees with the World Health Organization (WHO) indirect effects' data base, in which an out of proportion relation between the appearance of gynecomastia and the inhibitor proton pump use was demonstrated, which suggests that the mammary growth is a characteristic indirect effect of these antacid medicines.