Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 2002
Case ReportsLow-dose intravenous lidocaine as treatment for proctalgia fugax.
Proctalgia fugax is characterized by a sudden internal anal sphincter and anorectic ring attack of pain of a short duration. ⋯ Based on the experience reported in this case and the potential benefit of this treatment for proctalgia fugax, controlled studies comparing intravenous lidocaine with placebo should be conducted to confirm the observation and to provide a more concrete basis for the use of intravenous lidocaine for this indication.
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Reg Anesth Pain Med · Jan 2002
Intrathecal lidocaine causes posterior root axonal degeneration near entry into the spinal cord in rats.
The neurotoxicity of lidocaine is not fully understood, and the primary lesion of lidocaine-induced spinal neurotoxicity has not been defined. Here we examine the effects of various concentrations of intrathecally administered lidocaine. ⋯ Our results suggest that spinal lidocaine neurotoxicity after supra-clinical concentrations of lidocaine is limited initially to the posterior roots at their entry to the spinal cord, and the extent and severity of the lesions are closely associated with lidocaine concentration. Unlike severe lesions in rats injected with 20% lidocaine, mild lesions caused by lower concentrations may not manifest neurofunctional deficits.
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Reg Anesth Pain Med · Jan 2002
Gabapentin decreases membrane calcium currents in injured as well as in control mammalian primary afferent neurons.
Neuropathic pain following injury to peripheral sensory neurons is a common clinical problem and frequently difficult to treat. Gabapentin (GBP), a novel anticonvulsant, has significant analgesic effects in clinical neuropathic states and in relevant preclinical models, but its mechanism of action remains unclear. Because calcium currents play a significant role in neuronal function, this study was designed to assess the effect of GBP on the membrane voltage-activated inward calcium currents (I(Ca)) in dorsal root ganglia (DRG) primary afferent neurons of neuropathic versus control rats. ⋯ GBP, at clinically relevant concentrations, results in significant reduction of I(Ca) in both sham and neuropathic neurons, while in nonoperated rats reduced I(Ca) to a smaller degree. Sensitivity to drug was not affected by neuropathy. This current inhibition is partly voltage dependent. Depression of I(Ca) may be partly related to the binding of the drug to the alpha(2)delta modulatory subunit of the voltage activated calcium channels (VACC). Analgesia may be due to diminished release of neurotransmitter by sensory neurons, a Ca(2+)-dependent process.