Tramadol in acute pain

Tramadol has been in clinical use in Germany since the late 1970s and has proven effective in both experimental and clinical pain without causing serious cardiovascular or respiratory side effects. Moreover, the negligible abuse potential of tramadol has meant that it has never been a restricted drug, and it therefore very quickly became the most popular analgesic of its class in Germany. Although tramadol has been used in myocardial emergencies, in trauma and obstetric pain, or to supplement balanced anaesthesia, most studies have investigated postoperative patients. The focus of this article is to review clinical experience with tramadol in the treatment of acute postoperative pain. Tramadol, a synthetic opioid of the aminocyclohexanol group, is a centrally acting analgesic with weak opioid agonist properties, and effects on noradrenergic and serotonergic neurotransmission. In addition, these opioid and nonopioid modes of action appear to act synergistically. Tramadol has been shown to provide effective analgesia after both intramuscular and intravenous administration for the treatment of postoperative pain. The drug is available in formulations suitable for oral, rectal and parenteral administration. Clinically effective analgesic doses of tramadol were comparable to those of pethidine (meperidine) and about 10 times higher than those of morphine. While it is not recommended as a supplement to general anaesthesia because of its insufficient sedative activity, tramadol has been successful in the treatment of postoperative pain. A randomised double-blind study reported acceptable analgesia with postoperative intravenous tramadol 50mg, repeated once if required after 30 minutes. It produced an effect similar to that of morphine 5mg or the alpha 2 agonist, clonidine 150 micrograms. In another study, it was shown that the 50mg dose of tramadol fulfilled the requirements of an analgesic for the treatment of moderate postoperative pain, whereas for severe pain a higher dose was recommended. Tramadol is generally well tolerated, the most common adverse events being nausea and vomiting. In contrast to agents such as morphine and pethidine, clinically relevant respiratory depression is rarely observed during tramadol administration at equipotent doses and consequently it can be recommended for first-line management of postoperative pain instead of morphine. It is also associated with a low incidence of cardiac depression and significantly less dizziness and drows