With more patients taking opiates in medicine, it is important to note their effects on infertility. Studies of men taking low doses of heroin and methadone have shown decreased sperm motility, but no effect on sperm count or testosterone levels. High doses of opiates lower libido and can cause erectile dysfunction as well as impairments in sperm production.[1,5]
Opiates have been shown to act primarily on the HPG axis, by reducing LH and FSH, resulting in hypogonadotropic hypogonadism. Intrathecal opiates have the most profound effect on the HPG axis followed by intravenous, transdermal, and oral forms. The HPG axis depression results in decreased testosterone production and impaired spermatogenesis. Recently, functional opiate receptors have also identified on sperm membranes, but their function has yet to be determined. If confirmed, this would indicate the possibility of a direct toxic effect of opiates on sperm. Opiate inhibition is generally reversible with discontinuation of the drug.
Semin Reprod Med. 2013;31(4):286-292. © 2013 Thieme Medical Publishers