de Vries F, Bruin M, Lobatto DJ, et al. - Researchers analyzed the impacts of opioid use on pituitary function through this systematic review and meta-analysis. For articles published up to May 8, 2018, eight electronic databases have been searched. Fifty-two studies (22 low risk of bias) were involved representing 18,428 individuals, consisting of patients with chronic pain (n = 21 studies) or on maintenance treatment for opioid addiction (n = 9) and healthy volunteers (n = 4). Methadone, followed by morphine, was the most frequently used opioid. Data reported that hypogonadism prevalence was 63%. Hypogonadism occurs in more than half of male users of opioids, and hypocortisolism occurs in around one-fifth of all patients. Therefore it is advisable to periodically evaluate at least the gonadal and adrenal axes.