Researchers have found a direct link between sleep apnea and specific doses of methadone and benzodiazepines, according to a study published in the July 30 online version of Pain Medicine.
 
A study led by Lynn R. Webster, MD, conducted PSGs on 147 chronic pain patients who had been taking opioids around-the-clock for six months at a steady dose for at least four weeks.
 
Among the 75% who had abnormal sleep patterns, 39% had obstructive sleep apnea, 4% had sleep apnea of indeterminate type, 24% had central sleep apnea, and 8% had both central and obstructive sleep apnea.
 
A direct relation was found between the apnea–hypopnea index and the daily dosage of methadone but not to other around-the-clock opioids. In addition, there was direct relation between the central apnea index and the daily dosage of methadone and also with benzodiazepines.
 
The researchers concluded that the dose–response relation of sleep apnea in this class of opioids requires increased vigilance.
 
To read the abstract in Pain Medicine, click here.