Weighing the balance: how analgesics used in chronic pain influence sleep?

Pain and sleep share a bidirectional relationship, with each influencing the other. Several excellent reviews have explored this relationship. In this article, we revisit the evidence and explore existing research on this complex inter-relationship. The primary focus of the article is on the pharmacological treatment of chronic non-malignant pain and the main purpose is to review the effect of various pharmacological agents used in the management of chronic pain on sleep. This has not been comprehensively done before. We explore the clinical use of these agents, their impact on sleep architecture and sleep physiology, the mechanism of action on sleep parameters and sleep disorders associated with these agents. Pharmacological classes reviewed include antidepressants, opioid analgesics, anti-epileptics, cannabinoids and non-steroidal anti-inflammatory agents, drugs most commonly used to manage chronic pain. The objective is to help health professionals gain better insight into the complex effect that commonly used analgesics have on an individual's sleep and how this could impact on the effectiveness of the drug as an analgesic. We conclude that antidepressants have both positive and negative effects on sleep, so do opioids, but in the latter case the evidence shifts towards the counterproductive side. Some anticonvulsants are sleep sparing and non-steroidal anti-inflammatory drugs (NSAIDs) are sleep neutral. Cannabinoids remain an underexplored and researched group.

Is cognitive behavioural therapy for insomnia effective in treating insomnia and pain in individuals with chronic non-malignant pain?

AIM: This paper systematically reviews clinical trials investigating the effectiveness of cognitive behavioural therapy for insomnia and pain in patients with chronic non-malignant pain. METHOD: A systematic search of MEDLINE, PSYCINFO, EMBASE, CINHAL and Cochrane library and register of trials was conducted. RESULTS: Essential components of cognitive behavioural therapy for insomnia were included in all studies except for the cognitive restructuring component, which was not considered an intervention in one study. Interventions were provided by adequately trained clinicians. Significant within-group effect sizes (> 1) were observed in the intervention groups as compared with the control groups. Improvements were noted in sleep latency, sleep efficiency and wake after sleep onset times. Although improvements were noted in pain experienced by the participants, this was not a significant finding. CONCLUSIONS: These clinical trials demonstrate that cognitive behavioural therapy for insomnia is effective as an intervention for insomnia in individuals suffering from chronic non-malignant pain. Although pain and disturbed sleep are linked, cognitive behavioural therapy for insomnia alone may not be an effective solution for addressing chronic non-malignant pain. Trials of cognitive behavioural therapy for insomnia on a variety of chronic pain patients with disturbed sleep and with long-term follow-up are required to ascertain whether cognitive behavioural therapy for insomnia is an effective intervention to reduce pain and to add to increasing evidence that it is an effective intervention for insomnia in the chronic pain population.