[Systemic administration of alpha(2)-adrenoceptor agonists for postoperative pain reliefagonists for postoperative pain relief.].

The alpha(2)-adrenoceptor agonist clonidine has analgesic properties comparable to those of opioids after systemic administration. It also has antihypertensive, antiemetic, anxiolytic, sedative and antisialogogue effects and reduces the incidence of shivering. Thus, the pharmacodynamic profile of clonidine seems to suit it quite well for the special problems related to recovery from anaesthesia. The respiratory depression is weak, particularly in comparison with opioids. This paper reviews previous experience with systemic administration of alpha(2)-adrenoceptor agonists for postoperative pain relief. Especially in combination with low-dose opioids, clonidine leads to a similar or even better level of pain relief with significantly reduced adverse side effects compared with opioid mono-therapy, perhaps because different sites of action are addressed and influence nociception. Therefore, balanced postoperative analgesia including alpha(2)-adrenoceptor agonists, therefore seems to be a beneficial addition to differentiated postoperative pain relief.