Acta anaesthesiologica Scandinavica
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Psychomotor and cognitive dysfunction in cancer patients can be classified into two main categories according to etiology: disease-induced factors (metabolic disturbances, brain metastasis, pain, etc.) and treatment-related factors (drugs, antineoplastic therapy, etc.). In particular, the effects of chronic opioid administration in cancer patients have been subjected to investigations, and most studies have been engaged in assessment and treatment of the cerebral dysfunction. Early studies found that cancer patients in chronic oral opioid therapy had prolonged continuous reaction times, and that the opioids seemed to be mainly responsible for the prolongation. ⋯ Large doses of opioids are often required to control severe pain in cancer patients. As increased sedation and impaired psychomotor and cognitive functions often occur, a number of studies have investigated the use of amphetamine derivatives to counteract the sedative side-effects of opioid. These drugs seem promising during high-dose opioid therapy and their use may be particularly rewarding in poor opioid-responsive pain conditions such as incident and neuropathic pain.
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Cancer pain generally responds in a predictable way to analgesic drugs and drug therapy is the mainstay of treatment. A small proportion of patients, of the order of 20%, have pain that does not respond well to conventional analgesic management. Because opioid analgesics are the most important part of this pharmacological approach, a terminology has developed which centres around whether or not pain will respond to opioid analgesics. ⋯ The underlying pathophysiology remains unclear but abnormal metabolism of morphine is not the cause of a poor response to this drug. Patients with opioid-poorly-responsive-pain should be considered for treatment with the same opioid by an alternative (spinal) route or with an alternative opioid agonist administered by the same route (whether oral or parenteral), in conjunction with adjuvant analgesics such as tricyclic antidepressants. The most commonly used alternative oral opioids are phenazocine and methadone; transdermal fentanyl is an additional option.
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Morphine is a potent opioid analgesic widely used for the treatment of acute pain and for long-term treatment of severe pain. Morphine is a member of the morphinan-framed alkaloids, which are present in the poppy plant. The drug is soluble in water, but its solubility in lipids is poor. ⋯ M3G exhibits no analgesic effect after ICV or IT administration. Some studies do, however, indicate that M3G may cause non-opioid mediated hyperalgesia/allodynia and convulsions after IT administration in rats. These observations led to the hypothesis that M3G might be responsible for side-effects, hyperalgesia/allodynia and myoclonus seen after high-dose morphine treatment.
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Acta Anaesthesiol Scand · Jan 1997
Hemodynamic, sympathetic and angiotensin II responses to PEEP ventilation before and during administration of isoflurane.
Positive end-expiratory pressure (PEEP) ventilation and isoflurane anesthesia may opposingly affect the sympathetic nervous and renin-angiotensin systems. This study was performed to elucidate the modulatory effects of isoflurane anesthesia on the neurohumoral and cardiovascular responses to PEEP. ⋯ The data suggest that renin-angiotensin activation is important to attenuate the impact of PEEP ventilation on cardiovascular performance during administration of the sympathodepressant isoflurane. Interference with the renin-angiotensin system may cause cardiovascular decompensation in isoflurane anesthetized patients subjected to PEEP-ventilation.
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Acta Anaesthesiol Scand · Jan 1997
Long-term intrathecal infusion of morphine in the home care of patients with advanced cancer.
Fear of infections and other complications has made many clinicians avoid intrathecal application of morphine in chronic cancer pain. However, recent comparative studies show that, in long-term treatment, intrathecal morphine administration may give a more satisfactory pain relief with lower doses of morphine and fewer side-effects than epidural administration. In Montpellier Cancer Institute, first cancer pain patients received long-term intrathecal morphine as early as in 1979, and since then more than 400 patients have been treated. ⋯ Long-term intrathecal morphine infusion seems to provide satisfactory analgesia, few side-effects and a high degree of patient autonomy.