Triple Intrathecal Combination Therapy for End-Stage Cancer-Related Refractory Pain: A Prospective Observational Study with Two-Month Follow-Up

Introduction In cancer-related pain refractory to systemic opioids, intrathecal (IT) administration of morphine can be a useful strategy. In clinical practice, IT morphine is usually combined with other drugs with different mechanisms of action, in order to obtain a synergistic analgesic effect. However, the discussion on efficacy and safety of IT combination therapy is still ongoing. The aim of this observational study was to report the effects of an IT combination of low doses of ziconotide, morphine, and levobupivacaine in end-stage cancer refractory pain. Methods Sixty adult patients, 21 females and 39 males, were enrolled to an IT device implant. The mean visual analogue scale of pain intensity (VASPI) score was 88 ± 20 mm. All patients started with a triple combination therapy: the initial IT dose of morphine was calculated for each patient based on the equivalent daily dose of morphine; an oral/IT ratio of 400/1 was used. For ziconotide, a standard slow titration schedule was started at 1.2 μg/day and the initial dose of levobupivacaine was 3 mg/day. Results The initial IT mean doses of morphine, ziconotide, and levobupivacaine were 0.8 ± 0.3 mg/day, 1.2 mcg/day and 3 mg/day, respectively. At day 2, a significant reduction in VASPI score was registered (49 ± 17, p