Le tramadol dans les douleurs aiguës

Résumé

Le tramadol est un analgésique opioïde faible dont l’effet antalgique est efficace, par voie intraveineuse et intramusculaire chez l’adulte, dans le traitement des douleurs postopératoires. Les doses analgésiques cliniquement efficaces de tramadol sont comparables à celles de la péthidine (mépéridine) et environ dix fois plus élevées que celles de la morphine.

Le tramadol, opioïde de synthèse appartenant au groupe aminocyclohexanol, est un analgésique central qui présente une faible activité agoniste sur les récepteurs opioïdes ainsi que des effets sur la neurotransmission noradrénergique et sérotoninergique. Ces mécanismes d’action semblent agir de façon synergique. Le tramadol est associé à une faible incidence de dépression cardiaque et respiratoire et, ce qui est particulièrement important, présente un très faible potentiel de pharmacodépendance et d’usage abusif. Ce médicament est disponible en formes galéniques permettant une administration orale, rectale et parentérale.

Le tramadol est généralement bien toléré, les effets secondaires les plus courants étant nausées et vomissements. Contrairement à d’autres molécules telles que la morphine et la péthidine, une dépression respiratoire cliniquement significative n’est que rarement observée à des doses équianalgésiques de tramadol. Enfin, le risque d’usage abusif du tramadol est négligeable.

Le tramadol est fréquemment utilisé en analgésie contrôlée par le patient (PCA), et s’est révélé bien toléré. Il existe des variations individuelles très importantes quant aux besoins d’analgésiques; de ce fait le titrage individuel systématique des doses est nécessaire pour assurer un niveau satisfaisant de soulagement de la douleur. Les doses bolus et les doses de charge jouent un rôle décisif dans la réussite de la PCA.

Cet article présente un résumé de l’expérience clinique avec le tramadol dans la prise en charge de la douleur aiguë durant la période postopératoire.

English Abstract

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 α2 agonist, Clonidine 150µg. 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 metoclopramide.