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Updated: Mar 31, 2026

Electrophysiological Methods to Assess Peripheral Pain Block in an Anesthetized Rat
Published on: November 21, 2025
Neuraxial (epidural and intrathecal) opioids for intractable pain
Paul Farquhar-Smith1, Suzanne Chapman1
1Royal Marsden NHS Foundation Trust, London, UK.
Abstract:
1. Neuraxial opioids are considered for use in patients who have resistant intractable pain that fails to respond to other treatment options or pain that responds to analgesia but for which the doses required result in unacceptable side-effects. 2. Neuraxial opiods can be considered for both chronic non-malignant pain and chronic cancer-related pain. 3. Effectiveness in chronic non-malignant pain and cancer pain is exerted through the use of either single-agent drugs (opioids) or a combination of drugs: opioids, local anaesthetics and other drugs such as clonodine and ziconotide. 4. Complications of long-term continuous infusion therapy are related to the insertion process (haematoma), the mechanical device (both pump and catheter) and the long-term effects of the drugs. 5. Patients will require ongoing ambulatory monitoring and supportive care.
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