Coffein plus Analgetika—eine sinnvolle Kombination

Caffeine as a promoter of analgesic-associated nephropathy--where is the evidence?

Individual groups of nephrologists - in their responsibility for their patients - initiated a most controversial discussion whether or not caffeine - coformulated to analgesics - might initiate or sustain analgesic overdosing. The original sources (data) of such suspicion have got lost during the debate of the last two decades. Therefore, it seemed to be appropriate to investigate the original data background and the reasons why nephrologists started to suspect caffeine as a stimulant of analgesic overdosing by employing a systematic and exhaustive review of primary nephrological publications. Their selection followed a precise selection plan, including all epidemiological studies on analgesic-associated nephropathy, the original papers of all groups having been involved in those studies, further originals from the mainly involved countries (academically, politically), and any literature thereof cited as a proof. The following results emerged from the investigation: (i) The epidemiological studies warranted no conclusion about a role of caffeine in prompting excessive analgesic use. (ii) The identified groups of nephrologists provided not substantial data to advocate the said suspicion, except for the observation of a preferential choice of phenacetin-containing combinations, especially powder preparations. (iii) Only two cited original data sources revealed drug-seeking behaviour with phenacetin-containing preparations which subsided, after phenacetin was banned from the respective markets. Conclusively, it appears that there is no substantial data to support a pivotal role of caffeine in initiating or sustaining analgesic overdosing. However, there is strong data that phenacetin, by its psychotropic properties, may have caused drug-seeking behaviour and thus led to analgesic overdosing. This conclusion is convincingly supported by thorough pharmacokinetic investigations. Note: All caffeine-related statements within the reviewed literature have been collected in tables (referred to as Table SX) which are provided in full text for check on the following website: http://www.blackwellpublishing.com/products/journals/suppmat/FCP/FCP174/FCP174sm.htm

Experimentelle Untersuchung zur Wirkung von Acetylsalicylsäure kombiniert mit Coffein unter dem Aspekt eines Missbrauchspotentials

Zusammenfassung. Coffein als Bestandteil zahlreicher Schmerzmittel soll in Kombination mit einem Analgetikum Wirkungen entfalten, die den Missbrauch begünstigen. Als Beitrag zur Klärung dieses Problemkreises wurde nach einem 2-faktoriellen Plan die Wirkung von Acetylsalicylsäure (500 mg) und Coffein (50 mg und 100 mg) allein und in Kombination auf das psychische Befinden vor, während und nach der Induktion eines Schmerzreizes (Druckschmerz) über mehrdimensionale Selbstbeurteilungsverfahren und Variablen des kardiovaskulären Systems erhoben. Weiterhin wurden Aspekte der subjektiven Bewertung und der Präferenz der Einzelsubstanzen und des Kombinationsanalgetikums über Selbstbeurteilungsmethoden und ein verhaltensbezogenes Präferenzmaß erfasst.Die wichtigsten Ergebnisse sind: (1) Acetylsalicylsäure läßt keine Wirkungen auf die Variablen des psychischen und körperlichen Befindens erkennen. (2) Coffein reduziert negative Befindensaspekte, insbesondere Angst/Traurigkeit, eine Steigerung positiver Befindensaspekte ist nicht beobachtbar. Im Wahlverhalten zeigt sich eine Präferierung von Coffein als Monosubstanz. (3) Das Wirkungsprofil der Kombination ist schwerpunktmäßig durch eine Reduktion der Aspekte Erregtheit und Aktiviertheit geprägt. (4) Die Bewertung der Präparate lässt keine Hinweise auf eine Bevorzugung der Kombination erkennen.Damit stützen die Befunde die Annahme nicht, dass ein peripher wirksames Analgetikum wie ASS mit Coffeinzusatz aufgrund der Wirkungen des Coffeins bevorzugt eingenommen wird.

A safety assessment of fixed combinations of acetaminophen and acetylsalicylic acid, coformulated with caffeine

Overuse and abuse of phenacetin-containing mixed analgesics has contributed to end-stage renal disease. Combination analgesics, especially those coformulated with caffeine, have been implicated as imparting a greater risk of analgesic-associated nephropathy (AAN) than single or coformulated analgesics without caffeine. This has led to a recommendation that the sale of "two plus caffeine" analgesic mixtures be reclassified from over-the-counter to prescription only availability. There is a rational basis for coformulating acetylsalicylic acid (ASA) and acetaminophen (paracetamol) as this reduces the dose of each, without altering efficacy. The coformulation of caffeine with these analgesics has a significant adjuvant effect and increases analgesic efficacy 1.4-1.6-fold. Currently available animal and human data do not support the notion that the nephrotoxic risk from coformulated ASA and acetaminophen is higher than the risk from either ASA or acetaminophen alone, in equivalent analgesic doses. There are no epidemiological data that implicate caffeine in AAN, and only limited evidence that links excessive acetaminophen usage to renal disease. There is no evidence that caffeine increases analgesics papillotoxicity directly. The presence of caffeine in mixtures of analgesics are no more addictive than other sources of caffeine. There is no evidence to suggest that adding caffeine to analgesic mixtures enhances the potential for promoting analgesic misuse in the general population. Thus distinct therapeutic benefits of ASA, acetaminophen and caffeine appear to outweigh any known risk. It is doubtful if preventing the availability of these products will significantly affect the role of analgesic abuse/overuse in end-stage renal disease. Better risk management would come from a focused educational program, developed in a close collaboration between industry, healthcare professionals and consumer organizations, such a program must warn against the potential dangers of analgesic and non-steroidal anti-inflammatory drug misuse.

[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.