Testosterone Levels in People Taking Regular Low-Dose Sustained-Release Morphine for Persisting Breathlessness: An Exploratory Study

Background: The intermediate- and long-term effects of regular low-dose sustained-release (SR) morphine on the testosterone levels of people with persistent breathlessness are unknown.Methods: Exploratory analysis of a randomized controlled trial of the effects of regular SR morphine (0/8/16/24 mg every 24 hours) for persistent breathlessness associated with chronic obstructive pulmonary disease. Total testosterone was measured at baseline and at cessation (greater than or equal to three months on stable medication).Results: Among 20 participants (9 males; median treatment duration between measurements 169 days [IQR 162-175]), only 3 had substantial declines in testosterone levels during the study (morphine 8, 16, 24 mg groups). All three had worsening illness at the time of the second assessment. There was no apparent relationship between change in testosterone, morphine dose, and change in breathlessness.Conclusions: Substantial declines in testosterone were uncommon and were not apparently related to changes in morphine dose or breathlessness, but they were possibly related with worsening illness.