Men who take long-acting opioids for chronic pain are five times more likely to have low testosterone according to a Kaiser Permanente study.

The link between opioid painkillers and low testosterone has been known for some time, but this study — published in The Clinical Journal of Pain — was the first to show a difference in testosterone levels between short-acting and long-acting opioids.

The odds of having low testosterone were 4.78 times greater for men taking a long-acting opioid than a short-term opioid.

The study was performed using 81 men between 26 and 79 years old. All of the men had been taking an opioid painkiller for at least 3 months, and none had a previous diagnosis of low testosterone. Seventy-four percent of the men on long-acting opioids had low testosterone, compared to 34 percent of the men who used short-acting opioids.  

Oxycontin and Opana are two commonly prescribed long-acting opioid painkillers. Vicodin, and other hydrocodone blends are short-acting opioids. An estimated 4.3 million Americans use opioids on a daily basis.