A PROSPECTIVE, WITHIN-PATIENT, CROSSOVER STUDY OF CONTINUOUS INTRAVENOUS AND SUBCUTANEOUS MORPHINE FOR CHRONIC CANCER PAIN

The dose, efficacy and side effects of continuous intravenous Infusion (CIVI) of morphine were compared with continuous subcutaneous infusio n (CSCI) of morphine In patients with chronic cancer pain. Eligible pa tients were referred to the Palliative Care Program and were receiving a stable dose of CIVI of morphine. The design was a within-patient, o ne-way crossover, in which each patient provided data before and after a switch from CIVI to CSCI of morphine. ''Rescue'' doses were 50% of the hourly dose given every 2 hour as needed. Morphine was infused int ravenously (IV) and subcutaneously (SC) via a McGaw/AccuPro Volumetric Infusion Pump. After baseline data, including side effects and pain a ssessment, were obtained patients were evaluated twice daily for toxic ity and analgesic efficacy. Those who had a stable CIVI dose for 48 co nsecutive hr were crossed over to the CSCI at the same dose as the int ravenous (IV) phase. A stable dose was de;fined as no dose change, fou r or less rescue doses in the previous 24 hr, and a pain rating of non e ol mild. CIVI was considered equal to CSCI if these criteria were ma intained for 96 consecutive hr. Fifty-seven patients were entered, and 40 were evaluable (15 women and 25 men). The median age was 67 (range 30-83 penis). All 40 participants, after maintaining a stable dose th roughout the IV phase, crossed to the SC phase and remained on SC for at least 48 hr. Thirty-two patients maintained a stable nose throughou t tile nr and SC phases. The mean stable IV dose (day 2) was 5.05 mg/h r and the mean stable SC dose (day 4) was 5.7 mg/hr (P = 0.01). The me an number of rescue doses on day 2 runs 0.83 per 24 hr versus 0.80 per 24 hours on day 4 (P = 0.6). The mean categorical pain score on day 2 was 0.83, and on day 4, 0.85 (P = 0.7). The mean visual analogue scal e (VAS) on day 2 was 22.9 mm versus 17.6 mm on day 4 (P = 0.1). The me an incidence of side effects on day 2 was 1.7 and on day 4, 2.0 (P = 0 .2). No patient was withdrawn or had a dose reduction due to unaccepta ble toxicity. There were two reports of local toxicity (mild erythema) at the SC needle insertion point, which required a side change. All o f our 40 patients had adequate pain control with CM and CSCI morphine. Of the eight participants who were not maintained on the same IV and SC dose all had adequate pain control and a similar side-effect profil e on a higher SC morphine dose. These data suggest that the IV and SC routes are equianalgesic for most patients when administered as a cont inuous infusion. Pain control and side-effect profiles are quite simil ar and acceptable. SC morphine is art excellent alternative to IV morp hine in both inpatients and outpatients requiring parenteral morphine for pain. (C) U.S. Cancer Pain Relief Committee, 1997.