Opioid-induced sleep apnea: is it a real problem?

I 1997 the American Academy of Pain Medicine and the American Pain Society stated that “it is now accepted...that respiratory depression induced by opioids tends to be a short lived phenomenon, generally occurs only in opioid-naïve patients and is antagonized by pain. Therefore, withholding the appropriate use of opioids from a patient who is experiencing pain on the basis of respiratory concerns is unwarranted.”1 In addition, Papaleontiou et al. published a meta-analysis in 2010 on the effi cacy and safety of opioid intake in chronic non-cancer pain.2 Constipation, nausea, and dizziness represented the top three side effects, with a prevalence between 22% and 30%. However, obstructive or central apnea/hypopnea, hypoventilation during sleep, and impairment of respiratory drive remained unmentioned.2 Can general practitioners, pain therapists and oncologists reassure their patients regarding respiratory side effects in longterm treatment with opioids? It is without doubt, that for far too long suffi cient palliation has been withheld from pain patients, in fear of side effects, addiction, and misuse of opioids. However, improved knowledge combined with changing attitudes has helped to normalize the use of the most important relievers of pain, leading to a large increase in opioid prescription.3,4 Moreover, opioids are prescribed not only to relieve pain, but also, for example to alleviate dyspnea in patients with chronic pulmonary disorders.5 Finally, opiate addiction remains a growing and largely unsolved problem, leading to the incorporation of an increasing number of patients world-wide in methadone maintenance programs.6 Bearing in mind this widened use of opioids, observations of sleep related breathing disorders (SRBD) are alarming. Kelly et al. described fatal or life-threatening events in children who underwent adenotonsillectomy for obstructive sleep apnea. These children possessed genetic alterations that led to an increased morphine production from codeine.7 Many such reports of perioperative complications in sleep apnea patients have been published. In 2007 the broad spectrum of SRBD under opioids were described retrospectively by Walker et al.8 Besides obstructive disturbances, they found central apneas, ataxic or irregular respiration, and periods of sustained hypoventilation. However, we have to admit frankly that our knowledge of the pathophysiology of opioid-induced sleep apnea is still very opioid-induced sleep apnea: is it a Real problem? Commentary on Ramar et al. Adaptive servoventilation in patients with central or complex sleep apnea related to chronic opioid use and congestive heart failure. J Clin Sleep Med 2012;8:569-576.