Long-term efficacy and safety of oxycodone-naloxone prolonged release in geriatric patients with moderate-to-severe chronic noncancer pain: a 52-week open-label extension phase study

Abstract

Background: Two-thirds of older people suffer from chronic pain and finding valid treatment options is essential. In this 1-yearlong investigation, we evaluated the efficacy and safety of prolonged-release oxycodone-naloxone (OXN-PR) in patients aged ≥70 (mean 81.7) years.

Methods: In this open-label prospective study, patients with moderate-to-severe noncancer chronic pain were prescribed OXN-PR for 1 year. The primary endpoint was the proportion of patients who achieved ≥30% reduction in pain intensity after 52 weeks of treatment, without worsening bowel function. The scheduled visits were at baseline (T0), after 4 weeks (T4), and after 52 weeks (T52).

Results: Fifty patients completed the study. The primary endpoint was achieved in 78% of patients at T4 and 96% at T52 (P<0.0001). Pain intensity, measured on a 0-10 numerical rating scale, decreased from 6.0 at T0 to 2.8 at T4 and to 1.7 at T52 (P<0.0001). Mean daily dose of oxycodone increased from 10 to 14.4 mg (T4) and finally to 17.4 mg (T52). Bowel Function Index from 35.1 to 28.7 at T52. No changes were observed in cognitive functions (Mini-Mental State Examination evaluation), while daily functioning improved (Barthel Index from 53.1 to 61.0, P<0.0001). The Screener and Opioid Assessment for Patients with Pain-Revised score at 52 weeks was 2.6 (standard deviation 1.6), indicating a low risk of aberrant medication-related behavior. In general, OXN-PR was well tolerated.

Conclusion: This study of the long-term treatment of chronic pain in a geriatric population with OXN-PR shows satisfying analgesic effects achieved with a stable low daily dose, coupled with a good safety profile and, in particular, with a reduction of constipation, often present during opioid therapy. Our findings support the indications of the American Geriatrics Society, suggesting the use of opioids to treat pain in older people not responsive to acetaminophen or nonsteroidal anti-inflammatory drugs.

Keywords: chronic noncancer pain; constipation; geriatric; oxycodone/naloxone.

Figure 1

Flowchart of patient disposition throughout the study.

Figure 2

Distribution of OXN-PR daily dosages throughout the observation (expressed in oxycodone equivalents). Abbreviation: OXN-PR, prolonged-release oxycodone–naloxone.

Figure 3

Value of secondary outcomes (BPI, MMSE, and Barthel Index) at different time points of the observations. Abbreviations: BPI, Brief Pain Inventory; MMSE, Mini-Mental State Examination.

Figure 4

Value of Bowel Function Index at different time points of the observations.

Figure 5

Prevalence and severity of commonly observed opioid-related side effects and tremor at the different points of the observation. Notes: Symptom severity rated on an 11-point scale (0= absent; 1–3= mild; 4–6= moderate; 7–10= severe).