Original Articles: 2021 Vol: 13 Issue: 12
Neuropathic Pain Treatment using Opioid Analgesics and its usage Metrics
Department of Pharmaceutical Chemistry, Modern College of Pharmacy, Pune, India
The three cardinal symptoms of neuropathic pain, which are present to varying degrees in most patients, must be taken into account while treating pain related with nerve injury, such as diabetic neuropathy and post herpetic neuralgia. These feelings usually originate in the wounded nerve's domain, but they can sometimes spread to adjacent, normally innervated areas. Constant, burning dysesthesia pain is prevalent, and it might seem like the affected area. Paroxysmal pain, which is frequently brief, severe, and lancinating, is the second prominent symptom of neuropathic pain. It can happen on its own or be triggered by movement or tactile stimulus. The abnormal sense of pain in response to innocuous stimuli is the third symptom (allodynia). Light contact, warmth, and cold can all cause excruciating agony. Anticonvulsants and tricyclic antidepressants have a long history of use in the treatment of neuropathic pain. However, since a 1988 investigation concluded that opioid analgesics have little analgesic effect in this disease, the significance of opioid analgesics in the management of neuropathic pain has been seen as problematic. Because all of the neuropathic patients had long histories of "severely incapacitating pain that had resisted all previous treatments," including opioids, the study was critiqued.
Recent research suggests that opioid responsiveness is a continuation, with individuals with neuropathic pain requiring larger medication doses to achieve analgesia than patients with nociceptive pain. The evidence comes from studies involving brief opioid infusions, which suggest that neuropathic pain responds to opioid drugs in a classic dose-dependent manner, but that there is a shift to the right in the dose-response curve, implying that more of the drug is required for the same analgesic effect, with a higher risk of opioid-related side effects. A new randomised controlled post-operative trial that looked at pain reduction after a thoracotomy with intravenous buprenorphine backs up this claim. The key outcome metric was pain reduction of 50%. In the same 21 patients who developed post-thoracotomy neuropathic pain, pain alleviation was measured in the immediate postoperative period when the pain was mostly nociceptive and one month following surgery when the pain was mostly nociceptive. Individuals experiencing neuropathic pain required nearly twice the dose of buprenorphine required for patients with nociceptive pain to achieve 50% pain reduction.
In the treatment of neuropathic pain, the role of opioid analgesics versus adjuvant analgesics is unclear. There have been no head-to-head comparisons to determine which treatment is preferred. Anti-depressants and anticonvulsants are commonly prescribed as first-line therapy. Systematic reviews, on the other hand, demonstrate that there is minimal difference between these types of agents. An antidepressant or an anticonvulsant gives at least 50% pain relief to about one out of every three people with neuropathic pain. Even with combined treatment, up to 50% of patients who would benefit from an opioid analgesic may get insufficient pain relief.
Apart from trigeminal neuralgia, neuropathic pain is a challenging problem to deal with. In most circumstances, a reasonable goal is to make pain bearable, and this should be communicated to the patient. Because adjuvant analgesics frequently fail to control neuropathic pain, patients may benefit from the use of an opioid analgesic with a low risk of adverse effects.