Boswell G, Bekersky I, Mekki Q, Eisenach J
Fujisawa USA, Inc., Deerfield, Illinois, USA.
Clin Ther. 1997 Sep-Oct;19(5):1024-30. doi: 10.1016/s0149-2918(97)80054-9.
Epidural administration of clonidine, a partial alpha 2-adrenergic agonist, provides effective relief for patients with intractable cancer pain. However, clonidine's long plasma elimination half-life suggests a potential for plasma accumulation following repeated doses or constant infusion. Adult male and female cancer patients experiencing severe, intractable pain were administered a continuous epidural infusion (30 micrograms/h) of clonidine hydrochloride for 14 days. Plasma clonidine concentrations were determined for 31 patients using a radioimmunoassay with a limit of quantitation of 0.062 ng/mL. Mean (+/- SD) plasma clonidine concentration and calculated total body clearance after 7 days of infusion (respectively, 2.19 +/- 1.17 ng/mL, n = 24; 279 +/- 184 mL/min, n = 27) were comparable to those following 14 days of infusion (2.50 +/- 1.51 ng/mL, n = 19; 272 +/- 163 mL/min, n = 21). Clonidine does not appear to accumulate in the plasma compartment during prolonged (14-day) continuous epidural infusion in cancer patients.
可乐定是一种α2肾上腺素能部分激动剂，硬膜外给予可乐定可为顽固性癌痛患者提供有效缓解。然而，可乐定较长的血浆消除半衰期表明，重复给药或持续输注后可能会在血浆中蓄积。对患有严重顽固性疼痛的成年男性和女性癌症患者持续硬膜外输注盐酸可乐定（30微克/小时），持续14天。使用定量限为0.062纳克/毫升的放射免疫分析法测定了31例患者的血浆可乐定浓度。输注7天后的平均（±标准差）血浆可乐定浓度和计算得出的全身清除率（分别为2.19±1.17纳克/毫升，n = 24；279±184毫升/分钟，n = 27）与输注14天后的结果（2.50±1.51纳克/毫升，n = 19；272±163毫升/分钟，n = 21）相当。在癌症患者中进行长达14天的持续硬膜外输注期间，可乐定似乎不会在血浆中蓄积。
