Liguori, S., Gottardi, M., Micheletto, G., & Bruno, L. (2010). Pharmacological approach to chronic visceral pain. Focus on oxycodone controlled release: An open multicentric study. European Review for Medical and Pharmacological Sciences, 14(3), 185–190.

To determine the incidence of visceral pain and to evaluate the efficacy of oxycodone in the context of visceral pain

Patients with visceral pain stopped existing drug treatment and instead used controlled-release oxycodone for 15 days. Conversion was according to international guidelines. Dosage of the study drug was individualized. If by day 7 a patient did not achieve a pain-score reduction of at least 50% or if he or she experienced a severe adverse event, clinicians administered an alternative opioid. Investigators gathered pain scores at baseline and after 3, 7, and 15 days of treatment. The regimen permitted use of rescue medication, morphine sulfate.

• The sample was composed of 340 patients.
• Mean patient age was 64.1 years. Age range was 25–100 years.
• Of all patients, 46.5% were female and 53.5% were male.
• Of all patients, 94.9% had oncologic disease. The types of cancer that occurred most often in the sample were cancer of the colon (which 21% of patients had), pancreatic cancer (14%), and gastric cancer (10%). Of all patients, 57% had experienced pain, at levels that made them eligible for the study, for 0–3 months. Data reflect patients screened, not those included in the study.
• Of patients with visceral pain, 97.1% rated their pain as uncontrolled—that is, as 4–10 on the rating scale. More than two-thirds of patients rated their pain in the 7–10 range on the scale.
• At baseline, 65.5% of patients were taking strong opioids.

• Multisite
• Outpatient
• Pain centers in Italy

Prospective observational single-group trial

• Numeric rating scale, 0–10, to measure pain
• Four-point verbal rating scale, to measure patient's assessment of pain management effectiveness
• SF-12 Health Survey

All patients who entered the study completed the study. None had to switch to another opioid. Mean dose after titration was 50.1 mg/day controlled-release (CR) oxycodone. At all time points, pain scores had decreased from a baseline mean of 7.04. At day 15, the mean pain score was 2.37 (p < 0.00001). Authors noted some improvement in all domains of the SF-12, but these changes were not statistically significant. Few patients experienced more than mild adverse evens. The most frequent adverse events were nausea, constipation, and sleepiness.

In this study, use of CR oxycodone was associated with significant reduction in mean pain scores over a 15-day period, with minimal adverse events.

• The study had a risk of bias due to no appropriate control group.
• Individual physicians determined their own definitions of visceral pain.
• Authors did not provide data regarding rescue medication use or breakthrough episodes.
• The study was of short duration.
• Authors did not specify whether patients reported current, average, least, or worst pain levels.

This study showed CR oxycodone to be effective in producing significant pain reduction within three days and over 15 days. This finding warrants a study of long-term effect. CR oxycodone is one medication in the armamentarium of opioid formulations for pain management. The side effects of CR oxycodone are those to be expected with opioid use.