Ordóñez Gallego A, González Barón M, Espinosa Arranz E
Medical Oncology Service, La Paz University Hospital Madrid, Cátedra de Oncología y Medicina Paliativa, Universidad Autónoma de Madrid, Madrid, Spain.
Clin Transl Oncol. 2007 May;9(5):298-307. doi: 10.1007/s12094-007-0057-9.
Oxycodone is a semi-synthetic opioid with an agonist activity on mu, kappa and delta receptors. Equivalence with regard to morphine is 1:2. Its effect commences one hour after administration and lasts for 12 h in the controlled-release formulation. Plasma halflife is 3-5 h (half that of morphine) and stable plasma levels are reached within 24 h (2-7 days for morphine). Oral bioavailability ranges from 60 to 87%, and plasma protein binding is 45%. Most of the drug is metabolised in the liver, while the rest is excreted by the kidney along with its metabolites. The two main metabolites are oxymorphone--which is also a very potent analgesic--and noroxycodone, a weak analgesic. Oxycodone metabolism is more predictable than that of morphine, and therefore titration is easier. Oxycodone has the same mechanism of action as other opioids: binding to a receptor, inhibition of adenylyl-cyclase and hyperpolarisation of neurons, and decreased excitability. These mechanisms also play a part in the onset of dependence and tolerance. The clinical efficacy of oxycodone is similar to that of morphine, with a ratio of 1/1.5-2 for the treatment of cancer pain. Long-term administration may be associated with less toxicity in comparison with morphine. In the future, both opioids could be used simultaneously at low doses to reduce toxicity. It does not appear that there are any differences between immediate and slow-release oxycodone, except their half-life is 3-4 h, and 12 h, respectively. In Spain, controlled-release oxycodone (OxyContin) is marketed as 10-, 20-, 40- or 80-mg tablets for b.i.d. administration. Tablets must be taken whole and must not be broken, chewed or crushed. There is no food interference. The initial dose is 10 mg b.i.d. for new treatments and no dose reduction is needed in the elderly or in cases of moderate hepatic or renal failure. Immediate-release oxycodone (OxyNorm) is also available in capsules and oral solution. Side effects are those common to opioids: mainly nausea, constipation and drowsiness. Vomiting, pruritus and dizziness are less common. The intensity of these side effects tends to decrease over the course of time. Oxycodone causes somewhat less nausea, hallucinations and pruritus than morphine.
羟考酮是一种半合成阿片类药物，对μ、κ和δ受体具有激动活性。与吗啡的等效比为1:2。其作用在给药后1小时开始，控释制剂的作用持续12小时。血浆半衰期为3 - 5小时（吗啡的一半），24小时内达到稳定血浆水平（吗啡为2 - 7天）。口服生物利用度为60%至87%，血浆蛋白结合率为45%。大部分药物在肝脏代谢，其余部分及其代谢产物经肾脏排泄。两种主要代谢产物是羟吗啡酮（也是一种强效镇痛药）和去甲羟考酮（一种弱镇痛药）。羟考酮的代谢比吗啡更可预测，因此滴定更容易。羟考酮的作用机制与其他阿片类药物相同：与受体结合、抑制腺苷酸环化酶和神经元超极化，以及降低兴奋性。这些机制也在依赖性和耐受性的产生中起作用。羟考酮的临床疗效与吗啡相似，治疗癌痛的比例为1/1.5 - 2。与吗啡相比，长期给药的毒性可能较小。未来，两种阿片类药物可同时低剂量使用以降低毒性。速释和缓释羟考酮之间似乎没有任何差异，只是它们的半衰期分别为3 - 4小时和12小时。在西班牙，控释羟考酮（奥施康定）以10、20、40或80毫克片剂形式上市，每日两次给药。片剂必须整片服用，不得掰开、咀嚼或碾碎。不受食物影响。新治疗的初始剂量为每日两次10毫克，老年人或中度肝肾功能衰竭患者无需减量。速释羟考酮（奥施康定）也有胶囊和口服溶液剂型。副作用是阿片类药物常见的副作用：主要是恶心、便秘和嗜睡。呕吐、瘙痒和头晕较少见。这些副作用的强度往往会随着时间推移而降低。羟考酮引起的恶心、幻觉和瘙痒比吗啡略少。
