Treatment of severe cancer pain by low-dose continuous subcutaneous morphine

In a prospective and intraindividually controlled trial, we have compared the efficacy and safety of a continuous subcutaneous morphine infusion with conventional intermittent oral or subcutaneous morphine application. Twenty-eight in-patients with cancer pain received a short-term infusion lasting 2-42 days, and 8 out-patients underwent long-term infusion from 49 to 197 days during the terminal stage of their disease. Continuous subcutaneous morphine infusion significantly (P less than 0.001) improved both pain and quality of life when compared to conventional morphine application. With continuous infusion, 5-48 mg (median 19 mg) of morphine was required daily, significantly (P less than 0.001) less than the 10-90 mg (median 50 mg) necessary with conventional use. As a result of lower dosage, side effects under continuous infusion were infrequent and mild. Constipation occurred in 3 of the 36 patients and was always controlled by the addition of laxatives; no nausea, sedation or respiratory depression were observed. Signs of tolerance developed in 2 patients on long-term infusion, but the use of continuous subcutaneous methadone for 2 weeks reversed the tolerance. The study presented indicates that low-dose continuous subcutaneous morphine provides a valuable treatment modality for severe terminal cancer pain exhibiting a high degree of both efficacy and safety.