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 drowsiness than
morphine. Finally, the dependence and abuse potential with
tramadol is negligible. Comparative studies have generally shown that
tramadol is more effective than
NSAIDs for controlling
post operative pain. Use of a combination of
tramadol and
NSAIDs allows the
tramadol dose to be reduced and results in a lower incidence of adverse effects.
Patient controlled analgesia (PCA) with
tramadol has been frequently used and is well accepted by patients. Wide individual variations exist with regard to
analgesic requirements and, nowadays, it is generally accepted that adequate
pain management implies systematic individualisation of the
therapy, i.e. titration of the
analgesic effect to individual needs. Demand and loading doses play a decisive role in the success of PCA.
Analgesic failures requiring rescue medication are rare, but it should be stressed that these can always occur with weak
opioids. In conclusion,
tramadol can be recommended as a basic
analgesic for the treatment of moderate to severe
pain. In the event of
analgesic failure with
tramadol, there is no reason not to switch to more potent
opioids. Although no studies are available regarding its use in the management of
postoperative pain after day case surgery,
tramadol is frequently administered with good results in such patients. The most important side effects of
tramadol are
nausea and
emesis, which can often be prevented by slow injection and administration of a prophylactic
antiemetic such as metoclopramid