SAN FRANCISCO – Men with opioid-induced androgen deficiency had a modest improvement in two laboratory measures of pain tolerance after 14 weeks of testosterone gel treatment but no significant improvements in subjective measures of pain perception, findings from a randomized trial showed.
Thirty-six men in the study received daily 5-g applications of 1% testosterone gel, while 29 others received a placebo gel. The patients were about 50 years old on average and had been taking opioids for at least a month, mostly for back pain.
Dr. Shehzad Basaria
There was no statistically significant difference in overall subjective Brief Pain Inventory scores at week 14, but there was a nonsignificant trend for less pain interference with daily life among treated men and a trend on the Short Form (SF)–36 for fewer emotional problems.
In the lab, testosterone subjects had about a 5-W improvement in their toleration of a blunted pressure pin applied to their forearms, from a baseline tolerance of 27 W. Men in the placebo group had a tolerance reduction of about 5 W, from a baseline score of 19 W. That difference, and a modest improvement in thumb-pressure tolerance in the treated group, were both significant. Other trends toward greater pain tolerance in the testosterone group were not.
"Objective pain perception showed improvement in the testosterone arm," said lead investigator Dr. Shehzad Basaria, director of Boston University’s androgen clinical research unit. But that improvement trend was not seen with subjective pain perception, he noted, and the magnitude of the change was "small."
Nonetheless, "when you start an analgesic drug, laboratory pain improves before a person says he is subjectively better," Dr. Basaria said at the Endocrine Society’s annual meeting. "We need to do a larger and longer-term study to see if [the lab findings] translate into improvements in subjective" perceptions.
For now, he noted, "I would initiate testosterone replacement only for [current] indications. I would not initiate it for pain control. If pain improves, that’s a bonus."
Testosterone did not affect opioid requirements; there was no significant difference in opioid use between the two groups at the end of the study. At baseline, patients had a mean total testosterone concentration of 228 ng/dL and a mean free testosterone concentration of 44 pg/mL; dosing was adjusted in the testosterone arm at 2 weeks to achieve total serum concentrations of 500-1,000 ng/dL.
Dr. Basaria said he had no relevant financial disclosures. The study was funded by AbbVie Pharmaceuticals, makers of the AndroGel testosterone gel used in the study.