Endocrine and Metabolic Effects

Chronic opioid use has been found to have a strong impact on the hormonal system. The mechanism of these effects is believed to occur through opioid interaction with the hypothalamic-pituitary axis in humans. Opioids have been shown to affect the release of every hormone from the anterior pituitary including growth hormone (GH), prolactin, thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), and lutein-stimulating hormone (LSH). This has been shown to cause individuals on opioids for a significant period to have a marked increase in the production of adrenal corticosteroids and a marked decrease in the production of the sex hormones.

Of all of the endocrine problems observed, some of the most serious relate to the decrease of gonadotropin-releasing hormone (GnRH). The decrease in GnRH causes decreased levels of testosterone in males (also known as opiate-induced androgen deficiency), sexual dysfunction, infertility, fatigue, as well as loss of muscle and bone mass. The decrease in testosterone is of special concern because studies have suggested increased risk of metabolic syndrome and insulin resistance.

The decreased release of GnRH and subsequent decrease in LSH and follicle-stimulating hormone (FSH) may have dramatic clinical consequences in women as well. Decreased circulating levels of estrogen, low FSH, and increased prolactin can lead to bone loss, problems menstruating, and milk discharge from the breast.

Patients who have been on opioids for an extended period and who have symptoms of endocrine or metabolic problems should be evaluated and treated for them.