We investigated effects of flecainide, a Class IC sodium channel blocker, in the rat chronic constrictive injury (CCI) and ectopic nerve discharge models. In the behavioral evaluation, 2, 6, and 12 mg/kg flecainide were intravenously given to the CCI model, and a dose-dependent analgesic effect was shown on both thermal hyperalgesia and tactile allodynia. In the electrophysiological evaluation using the ectopic nerve discharge model produced by saphenous neurectomy, i.v. administration of 2, 6, and 12 mg/kg flecainide suppressed spontaneous discharge at the peripheral nerve level in a dose-dependent fashion as with the behavioral evaluation, but flecainide did not affect nerve conduction at the dose of 12 mg/kg.

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Introduction: For decades, morphine was the only strong opioid for the treatment of cancer pain in Japan. From March 2002, transdermal fentanyl patch has been applied to cancer patients previously treated with morphine. As a consequence, opioid rotation from morphine to fentanyl patch (Durotep TM patch) became major concern for physicians to control cancer pain in our country. In this article, we would like to introduce why and how we rotate the opioid, incidence of side efffects, and how we control breakthrough pain in our hospital. Patients: During the period of March 2002 to July 2002, 12 patients were entrusted to the anesthesiology pain service from difficulty in controlling morphine side effects. Primary cancer of the patients were 4 stomach, 2 gallbladder, 1 liver, 1 pancreas, 1 ovarian, 1 breast, 1 thyroid, and 1 lingual cancer. All patients were given morphine either orally, rectally, or intravenously and were scheduled for opioid rotation. They were all suffering from intractable side effect of morphine, possible digestive tract obstruction, and/or pruritis. Methods: Direct conversion from oral morphine to transdermal fentanyl with the ratio of 100:1 was basical ly enforced, however, varied depending on patient status. We also gave intravenous morphine using patient controlled analgesia (PCA) for rescue in several patients with severe breakthrough pain. Numeric rating scale (NRS), nausea score and drowsiness score was obtained for 72 hours during the rotation. Constipation was not evaluated as this study was designed for only 72 hours. Results: The median Numeric rating scale (NRS) at rest decreased from 4.5 to 3.0 at 72 hours after the rotation, however not significant. Nausea was present in 10 patients, and resolved completely in 6 patients. There were no significant increase in drowsiness score. One patient with pruritis, possibly due to morphine, disappeared soon after the end of rotation. Conclusion: Opioid rotation to transdermal fentanyl patch, under discreet assessment and rotation planning, is beneficial for cancer pain relief in patients requiring strong opioid analgesics if they were naive to previously given morphine.

To evaluate an adhesive tape containing 60% lidocaine (Penles(R)), we used a pain thermometer and pressure algometer to measure pain thresholds of superficial and deep pain in 20 adult volunteers to whose arms a 60% lidocaine tape or placebo tape was applied. The tapes were put on the forearms of volunteers, and pain thresholds were measured before and 15, 30, 60, 90, 120 min after application. In the lidocaine tape group, the threshold of superficial pain significantly increased compared to the placebo tape group after 60 and 90min. The deep pain threshold increased significantly in both the lidocaine and placebo tape groups, but no significant difference was observed between them. An adhesive tape containing 60% lidocaine is useful for reducing superficial pain, but we were unable to prove any effect on deep pain threshold within 120min after application of the tape.