Opioid-induced or pain relief-reduced symptoms in advanced cancer patients?

While opioids in increasing doses may produce adverse effects, the same adverse effects may be associated with poor pain control. Moreover, in the clinical setting symptomatic treatment and illness may balance the outcome of opioid titration. Some adverse effects may tend to disappear continuing the treatment in a long-term period.

The aim of this study was to monitor the effects of a rapid opioid titration combined with symptomatic treatment in patients with poor relief and to monitor these changes in the following period of 20 days.

A consecutive sample of 35 patients admitted to an acute Pain Relief and Palliative Care Unit were titrated with opioids, according to a department policy, allowing administration of parenteral opioids to assist opioid titration with oral or transdermal opioids.

Thirty-three patients were followed up for the period of the study. Pain was adequately controlled and doses were opioid doses were stable after a mean of 40 h. Opioid escalation index (OEI) was extremely high initially, and then progressively declined at the following study intervals. Weakness and nausea and vomiting did not change, as well as confusion and appetite. Drowsiness, constipation and dry mouth significantly increased and then did not change, although a significant decrease in drowsiness was subsequently observed. Well-being improved some weeks after opioid stabilization. In multivariate analysis, drowsiness and dry mouth were correlated to opioid doses.

The effects reported were often due to multiple causes. A rapid decrease in pain intensity induced by rapid opioid titration does not produce changes in weakness, nausea and vomiting, appetite. While constipation appears the most relevant problem, resistant to common symptomatic treatment, drowsiness initially produced by acute opioid dose increase and the achievement of pain relief, tends to spontaneously decrease, probably as the result of late tolerance. Improved well-being may be the late positive effect of pain relief, also influenced by the setting of home care.