Long-acting morphine for pain control in paediatric oncology

Guidelines for treatment of paediatric cancer pain recommend the usage of long-acting morphine. However, published paediatric experience with this drug is restricted to 147 children not systematically evaluated, and thus insufficient. We aimed to systematically analyse the age-dependent effects and adverse effects of long-acting morphine in paediatric cancer patients.

Ninety-five children aged 1 to 19 years were enrolled in a collaborative retrospective study conducted over seven-and-a-half years. Pain was scored according to a numeric rating scale (NRS, range 0 to 5), and the corresponding medication was recorded.

In 83 children documentation period started during morphine treatment (71, oral long-acting; 1, rectal; 11, IV). Mean oral/equivalent morphine starting dose was 1.3 mg/kgbw/d (SD 0.9). Mean end dose was 2.8 mg/kgbw/d (SD 2.7). Infants aged < 7 years received the highest average dose (2.6 mg/kgbw/d, SD 2.8), while patients > 12 years received the lowest dose (1.4 mg/kgbw/d, SD 1.1). Median pain intensity decreased from score 1.0 (mean 1.2) NRS at the beginning to 0 (mean 0.6) NRS at the end. The proportion of patients scoring > 2 NRS (severe or most severe pain) under morphine treatment decreased from 26 to 12% (P = 0.08). In children > 12 years pruritus was frequently observed (23% of patients). In all age groups, there were no severe adverse effects during the study period.

In paediatric haematology/oncology, pain control by oral long-acting morphine proved to be safe and effective even in the very young patients. The pharmacological properties of long-acting morphine are ideally suited for paediatric use, combining efficacy and compatibility.