Opioid in chronic pain

Tramadol Mixed effects weak P-agonist, moderate SERT inhibitor, weak NET inhibitor Analgesia Moderate pain adjunct to opioids in chronic pain syndromes Duration 4-6 h Toxicity Seizures... 

Sufka (1994) recommended the conditioned place preference paradigm as a novel approach for assessing effects of opioids in chronic pain induced in rats by... 

Vallerand AH. The use of long-acting opioids in chronic pain management. Nurs Clin North Am 21II 13 38(3) 4. 5 45. 

The role of NSAIDs and opioids in chronic non-malignant pain has been discussed however, a review of adjuvant agents... 

Acute abstinence syndrome (withdrawal) - In chronic pain patients in whom opioid analgesics are abruptly discontinued, anticipate a severe abstinence syndrome. This may be similar to the abstinence syndrome noted in patients who withdraw from heroin. Severity is related to the degree of dependence, the abruptness of withdrawal, and the drug used. Generally, withdrawal symptoms develop at the time the next dose would ordinarily be given. 

The causes and mechanisms of chronic pain syndromes are diverse (Lance 8c McLeod, 1981). A similarity with depression has been noted by several authors and it has been suggested that chronic pain syndromes might result from reduced activity in serotonergic systems involved in pain suppression and mood control (Moldofsky, 1982). Other authors have suggested that a causative factor in chronic pain syndromes might be abnormally low concentrations or activity of endogenous opioids, particularly beta-endorphin (Lip-man et al., 1990). 

Use of opioid drugs in acute situations may be contrasted with their use in chronic pain management, in which a multitude of other factors must be considered, including the development of tolerance to and physical dependence on opioid analgesics. 

Opioids are used for the treatment of moderate to severe or very severe pain of acute or chronic type (Stein, 1999). Nearly all forms of pain are sensitive to opioid treatment and in contrast to traditional opinions even neuropathic pain is reasonably sensitive to higher doses of opioids. This was clearly shown in well-controlled clinical studies (Watson, 2000). The most important use of opioids in acute pain treatment is postoperative pain, whereas treatment of cancer pain, often accompanied by a neuropathic pain component, is the classical domain of chronic opioid treatment. 

Reder, R.F.. Opioid formulations tailoring to the needs in chronic pain, Eur. J. Pain. 2001, 5, Suppl A, 109-111. 

Kalso, E. etal., Recommendations for using opioids in chronic non-cancer pain, Eut J. Pain, 7,381,2003. 

Dews TE, Mekhail N. Safe use of opioids in chronic noncancer pain. Cleve Clin J Med. 2004 71 897-904. 

Even the most severe acute pain (that lasting hours to days) can usually be well controlled—with significant but tolerable adverse effects—with currently available analgesics, especially the opioids. Chronic pain (lasting weeks to months), however, is not very satisfactorily managed with opioids. It is now known that in chronic pain, presynaptic receptors on sensory nerve terminals in the periphery contribute to increased excitability of sensory nerve endings (peripheral sensitization). 

It has long been known that stress can elevate the pain threshold. In rodents this may be quantified by measuring the increase in the pain threshold following prolonged unavoidable foot shock. Under conditions of environmental stress, the pain threshold has also been shown to increase in man. Such effects have been attributed to a rise in opioid peptides in the cerebrospinal fluid (CSF). Conversely, in chronic pain syndromes, the CSF concentration of the endorphins decreases. 

Kalso, E., Edwards, J. E., Moore, R. A., and McQuay, H. J. (2004). Opioids in chronic non-cancer pain Systematic review of efficacy and safety. Pain 112, 372—380. 

In addition to these opioid mechanisms, nonopioid mediated pathways, e.g. serotonin, are important in pain. There is suggestion that opioid mechaiusms are more important in acute severe pain, and nonopioid mechanisms in chronic pain, and that this may be relevant to choice of drugs. 

Roberts LJ, Finch PM, Goucke CR, Price LM. Outcome of intrathecal opioids in chronic non-cancer pain. Eur J Pain 2001 5(4) 353-61. 

MoUoy AR. The role of opioids in chronic nonmalignant pain. Mod Med Anst 1999 42 52-61. 

E Oxycodone/acetaminophen would be the most appropriate drug to start for this patient s acute postsurgical pain. The onset of action is rapid, and it can be titrated to effect. Morphine and meperidine have active metabolites that can accumulate in this patient with renal dysfunction, increasing the risk for seizures, sedation, and respiratory depression. The fentanyl patch is primarily indicated in chronic pain. The onset is slow, and the patches cannot be titrated up rapidly to cover acute pain, nor titrated down as the patient recovers and requires less opioid. 

American Academy of Pain Medicine and the American Pain Society also advocate the prudent use of narcotic analgesics for the treatment of chronic pain (15,16). The widespread use of opioids in chronic, nonmalignant pain, however, is still somewhat controversial because of the lack of substantial evidence from long-term controlled studies demonstrating effectiveness in this setting (17). The clinical use of opioids in different types of pain and in different clinical settings has been reviewed in detail in a recent book (18). 

DeLeo JA, Tanga FY, Tawfik VL (2004) Neuroimmune activation and neuroinflammation in chronic pain and opioid tolerance/hyperalgesia. Neuroscientist 10 40-52... 

Manchikanti L, Atluri S, Trescot AM, Giordano J (2008) Monitoring opioid adherence in chronic pain patients tools, techniques, and utility. Pain Physician 11(2 Suppl) ... 

In this chapter, we will review the analgesic sites of action as a mechanistic and multimodal approach to pain medicine and chronic pain management The mainstay of pain management has been opioid therapy, but, with the increasing knowledge of pain mechanisms, adjuvant medications are gaining a more prominent role in chronic pain management. 

Martin TJ, Eisenach JC. Pharmacology of opioid and nonopioid analgesics in chronic pain states. / Pharmacol Exp 77/er 2001 299 811-817. 

Chronic pain because its activity differs from that of opioids, neuraxial clonidine is potentially useful as an analgesic adjunct to opioids or as monotherapy in patients developing opioid tolerance. In limited studies, there is no histopathological evidence against its use however, there are insufficient data regarding long-term clonidine administration in chronic pain patients. 

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