Lansoprazole is a new proton-pump inhibitor that has been proven safe
and effective in the treatment of gastroesophageal reflux disease (GER
D) and peptic ulcer disease. In rats, the drug inhibited testosterone
synthesis and was associated with Leydig cell tumours. To determine th
e effect of a high therapeutic dose of lansoprazole (60mg day) on male
hormone levels and gonadal function, a randomised double-blind parall
el study was conducted. 32 healthy volunteers participated for 8 weeks
. Endocrine profiles included serum testosterone, luteinising hormone
(LH), follicle-stimulating hormone (FSH), sex hormone-binding globulin
(SHBG), dehydroepiandrosterone sulfate (DHEA-S), prolactin, estradiol
, cortisol and thyroid function. As further evaluation of an effect on
hormones, testes were monitored for changes in size and breasts for g
ynaecomastia. Sexual function parameters were assessed by semen analys
es and a sexual function questionnaire. Testosterone levels tended to
increase slightly in the lansoprazole group and decrease slightly in t
he placebo group. While the difference between groups was statisticall
y significant, the magnitude of changes was small and not clinically s
ignificant. Overall, there were no clinically significant changes in h
ormone levels. All testicular and breast measurements remained within
normal range. Similarly, no clinically significant differences between
treatment groups occurred in either semen analysis or sexual-function
parameters.