Intrathekale und epidurale Applikation von Nichtopioidanalgetika zur Therapie akuter und chronischer Schmerzen

[Peridural application of ropivacaine and clonidine for pain therapy after prostatectomy]

OBJECTIVE

The aim of this study was to find out if ropivacaine with clonidine can be successfully used after radical retropubic prostatectomy.

MATERIAL AND METHODS

A total of 86 patients were randomized into two groups each consisting of 43 patients. Patients in group 1 received epidural bupivacaine/morphine/clonidine and those in group 2 ropivacaine and clonidine. If necessary analgesic, antiemetic or antihistamine drugs were administered. Pain on a visual analogue scale (VAS), motoric and sensoric disturbances, sedation, itching, nausea and vomiting, hypotension, need of antihistamines, naloxon, antiemetics, ephedrine, and analgesics were also documented.

RESULTS

Differences in sedation, itching, nausea and vomiting, motoric and sensoric disturbances, need of antihistamines, antiemetics, and ketoprofen were significant, the other parameters did not show any significant differences.

CONCLUSIONS

We recommend the use of ropivacaine with clonidine in the postoperative pain management after radical retropubic prostatectomy.

The first in vivo experience of the effects of the continuous intrathecal infusion of clonidine on the locus coeruleus in the regulation of cerebral blood flow: a TCD study

This was a study of the action of continuous intrathecal clonidine infusion on the locus coeruleus in the regulation of cerebral blood flow (CBF) by means of a test of the activation of the locus coeruleus (cold pressure test, CPT).

METHOD

The effects on CBF of intrathecal clonidine used for analgesic purposes in a patient with a chronic painful benign syndrome were studied by means of transcranial Doppler sonography (TCD) before and after administering the CPT.

RESULTS

TCD with the infusion device activated revealed an increase in CBF velocities compared with those recorded when the device was inactivated. During CPT with the infusion device inactivated, TCD showed a decrease in CBF velocity: this decrease was less when the device was activated.

CONCLUSIONS

Our results suggest that the intracerebral vascular responses induced by CPT and intrathecal clonidine infusion may be related to a sympathetic regulating mechanism of cerebral vascularization, possibly mediated by locus coeruleus.

[Pharmacotherapy of cancer pain : 2. Use of opioids.]

The adequate use of opioids in the treatment of chronic cancer pain requires sound knowledge of selection criteria for the various opioids, the routes of administration, dosages, dosing schemes and possible side effects. Drug selection depends on the intensity of pain rather than on the specific pathophysiology. Mild to moderate pain can often be treated effectively by so-called "weak" opioids. These include codeine, dihydrocodeine and dextropropoxyphene. Non-opioid analgesics, like acetylsalicylic acid or paracetamol can be added according to the "analgesic ladder" proposed by the World Health Organization (WHO). If adequate pain relief is not achieved "strong" opioids are required. The route of administration that is the safest and the least invasive for the patient should be chosen. Non-invasive (oral, rectal, sublingual, transdermal and intranasal) and invasive routes (intravenous, subcutaneous, spinal and epidural) are available (Table 8). Noninvasive routes are preferred, and most patients can be maintained on oral opioids. Alternatively, in some patients pain can be managed by the sublingual (buprenorphine) route. A transdermal preparation exists for fentanyl, but has not yet been approved for the German market. If the oral route cannot be used or if large doses are required, it will be necessary to change to an invasive route. Intravenous bolus injections provide the fastest onset of analgesic action. They are mostly used in very severe pain. Repeated injections can be avoided by using intravenous or subcutaneous infusions. Various types of pumps delivering analgesics at constant basal infusion rates with the option of rescue doses in case of breakthrough pain are available (patient-controlled analgesia=PCA). Opioids frequently used for s. c. infusion are morphine and hydromorphone. Adjuvant drugs (antiemetics, anxiolytics) can be added. Epidural or intrathecal administration of opioids should only be used in intractable pain or if severe side effects, such as sedation and confusion, will arise with systemic opioids. Morphine, hydromorphone, fentanyl and sufentanil have been used, as have other additional compounds (e.g. local anaesthetics, clonidine). Intracerebroventricular application of morphine has been used only occasionally. In all cases, opioids should be given on to a fixed time schedule thereby, preventing pain from recurring. Additional rescue doses (approximately 50% of baseline single dose) are given for break-through pain. The most frequent side effect of opioids is constipation, and the administration of laxatives is often recommended (Table 5). Nausea, vomiting, sedation and confusion mostly occur in the beginning of opioid therapy. In contrast to constipation, tolerance to these effects develops within days or weeks. True dependence or psychological addiction rarely occurs in patients with chronic cancer pain. In most cases, progression of the underlying disease associated with increasing tissue damage and increasing pain is found. Fear of dependence and addiction often contributes to undertreatment of patients suffering from chronic cancer pain.