Painkillers containing opiods are often prescribed to manage pain that is disrupting sleep. However, a study led by the University of Warwick found that patients on a low to high dose of opioids reported only a small improvement in sleep quality.
Warwick/UK; Lausanne/Switzerland — Evidence that taking opioids will help people with chronic pain to sleep better is limited and of poor quality, according to an interdisciplinary team of psychologists and medics from the University of Warwick in partnership with Lausanne University Hospital, Switzerland. The small reported improvements were not always straightforward and might be offset by excessive daytime sleepiness and increased risks of sleep apnoea which can be overseen if monitoring is not appropriate.
Their study, a systematic review of existing research on the effects of opioids on sleep, has been published in Sleep Medicine Reviews.
Replacing One Evil with Another?
Long-term chronic pain, has a debilitating impact on people’s life. Sleep disruption is a particularly frequent issue for patients with chronic pain, with a vicious cycle building between bad nights and increased pain. Patients with chronic pain are often empirically prescribed opioids to reduce their pain enough to get a good night’s sleep, but there has been little investigation of whether this is a safe and effective intervention.
The researchers conducted a comprehensive systematic review of existing literature that examined the effects of opioids on sleep quality. As part of this, they conducted a meta-analysis of data from these studies, combining the results of 18 studies which were then narrowed down to 5 with comparable data.
They found that research on opioid effects on sleep quality was limited and of poor quality, often with potential publication bias and conflicts of interest, and rarely testing patients for sleep apnoea prior to and during the study. Patients reported a small improvement in sleep quality when using opioids but that was not consistent with results derived from sleep assessment technologies, such as the total time and the percentage of time in deep sleep, which did not show an improvement.
Certain studies reported calmer sleep with less movement but the examined articles frequently did not examine the wider effects of opioid therapy such as subsequent functioning during the day. Where they did, reports of sedation and daytime sleepiness were very frequent.
Opioids are known to affect the brain mechanism that controls breathing. This can potentially create sleep apnoea events where individuals experience pauses or obstructions in breathing, like a choking sensation, resulting in snoring, gasping for air, dry mouth and even a headache in the morning. Insomnia is known to be 42 % more likely among people with chronic pain prescribed opioids than controls without opioids.
Despite this, there was some evidence that low-medium dosed opioids could help improve sleep quality in some patients in the short term, but the effect was small and requires more investigation. For those prescribed a high dose of opioid therapy it didn’t necessarily bring out better results.
The researchers are calling for better quality research into the effects of painkillers on sleep quality, as well as better information for patients from clinicians when considering opioid therapy.