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Resumen: Se realiza una revisión descriptiva sobre la inyección de ácido tranexámico en el espacio subaracnoideo. Se destaca que un error puede tener consecuencias catastróficas sobre el paciente, con un alto porcentaje de mortalidad. Se analizan las posibles causas que pueden llevar a la inyección errónea. Se advierte sobre la existencia de preparaciones de ácido tranexámico de similar apariencia a las de la bupivacaína de uso intratecal. Se describe el cuadro clínico de la complicación, el mecanismo de toxicidad, los tratamientos utilizados, y la evolución de los casos relatados en las referencias encontradas. Se discuten estrategias para evitar la complicación, señalando que la seguridad no debe basarse en la perfección humana, sino en medidas que dificulten cometer errores.

Summary: A descriptive review of tranexamic acid injection in the subarachnoid space is performed. A point is made that this error may have catastrophic consequences on the patient with a high percentage of mortality. Possible causes that can lead to an erroneous injection are analyzed. A warning is made about tranexamic acid preparations being similar in appearance to those of bupivacaine for intrathecal use. The study describes the clinical manifestation of this complication, the toxicity mechanism, treatments used, and the evolution of the cases reported in the references found. Strategies to avoid complications are discussed, pointing out that safety should not be based on human perfection, but on measures that make it difficult for humans to make mistakes.

Resumo: Faz-se uma revisão descritiva sobre a injeção de ácido tranexâmico no espaço subaracnóideo. Ressalta-se que é um erro que pode ter consequências catastróficas para o paciente com um elevado percentual de mortalidade. Faz-se uma análise das possíveis causas que podem levar ao uso equivocado de ácido tranexâmico devido a existência de preparações semelhantes em aparência às da bupivacaína para uso intratecal. Descreve-se o quadro clínico da complicação, o mecanismo de toxicidade, os tratamentos utilizados e a evolução dos casos relatados nas referências encontradas. Discute-se estratégias para evitar complicações, ressaltando que a segurança não deve ser baseada na perfeição humana, mas em medidas que dificultem o erro do ser humano.

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AIMS: Intrathecal injection of morphine presents analgesic and antiedematogenic effects in rats. However, it is unknown whether tramadol, which possess a mixed mechanism of action, can also produce analgesic and antiedematogenic effects similarly. MAIN METHODS: Male Wistar rats received carrageenan and LPS in the right knee joint. Tramadol (10 µg) was injected intrathecally 20 min before articular LPS injection. Incapacitation and articular edema were measured 5 h after LPS stimulation. Synovial fluid was collected for leukocyte counting and western blot analysis. Whole joint and lumbar spinal cord were also collected for histology and immunohistochemistry, respectively. Intrathecal pretreatments groups were with the NKCC1 blocker bumetanide, TRPV1 agonist resiniferatoxin, µ-opioid receptor antagonist CTOP and serotonergic neurotoxin 5,7-DHT, all previously to tramadol. KEY FINDINGS: Tramadol treatment caused the reduction of incapacitation and edema. It also reduced c-Fos protein expression in the spinal cord dorsal horn and slightly reduced TNF-α levels in synovial fluid, but neither reduced cell migration nor tissue damage. Bumetanide and resiniferatoxin prevented the analgesic and antiedematogenic effects of tramadol. CTOP prevented the analgesic and the antiedematogenic effects, but 5,7-DHT prevented only tramadol-induced analgesia. SIGNIFICANCE: Spinal NKCC1 cotransporter and peptidergic peripheral afferents seem to be important for the analgesic and antiedematogenic effects of tramadol, as well as µ-opioid receptor. However, the monoamine uptake inhibition effect of tramadol seems to be important only to the analgesic effect.

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BACKGROUND AND OBJECTIVES: Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats. METHODS: A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250-300g) aged 12-16 weeks were randomly divided into 2 treatments [100 and 800µg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis. RESULTS: Rats in all the groups exhibited normal pinch-toe testing response (score=0) and normal gait at each observed time (motor function evaluation score=1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p=0.044; 2, 5, 0, p=0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800µg group than those in the 100µg and Control Groups (5, 3, 0, p=0.048, respectively). CONCLUSION: Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.

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Abstract Background and objectives Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats. Methods A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250-300 g) aged 12-16 weeks were randomly divided into 2 treatments [100 and 800 µg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis. Results Rats in all the groups exhibited normal pinch-toe testing response (score = 0) and normal gait at each observed time (motor function evaluation score = 1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p = 0.044; 2, 5, 0, p = 0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800 µg group than those in the 100 µg and Control Groups (5, 3, 0, p = 0.048, respectively). Conclusion Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.

Resumo Justificativa e objetivos A administração intratecal de anti-inflamatórios não esteroides é mais eficaz no tratamento da dor pós-operatória. Anti-inflamatórios não esteroides, como o (S)-(+)-cetoprofeno, pode ser eficaz em doses intratecais inferiores às parenterais. A segurança pré-clínica relativa à possível neurotoxicidade associada ao (S)-(+)-cetoprofeno intratecal não foi avaliada. Neste estudo avaliamos a neurotoxicidade do (S)-(+)-cetoprofeno administrado por via intratecal em ratos. Métodos Conduzimos um estudo experimental randomizado e controlado por placebo em ratos Sprague-Dawley (250-300 g) com idades entre 12 e 16 semanas. Eles foram randomicamente divididos em dois grupos de tratamento [100 e 800 µg de (S)-(+)-cetoprofeno] e um de controle (água estéril). Cateteres intratecais foram colocados através do espaço atlantoaxial nos ratos anestesiados. Testes de pinça, avaliações da função motora e exames histopatológicos da medula espinhal e das raízes nervosas foram realizados nos dias 3, 7 e 21 do estudo. Os cortes da medula espinhal foram avaliados por microscopia de luz para vacuolização do funículo axonal dorsal, perda de mielina axonal, cromatólise neuronal, neurite, inflamação, aderências e fibrose das meninges. Resultados Em todos os grupos, os ratos exibiram resposta normal ao teste de pinça (pontuação = 0) e marcha normal em cada tempo observado (escore de avaliação da função motora = 1). A neurotoxicidade foi maior com os tratamentos nos dias 3 e 7 do que no dia 21 (2, 3, 0, p = 0,044; 2, 5, 0, p = 0,029, respectivamente). No dia 7, os escores totais refletindo o dano neuronal foram maiores no grupo com 800 µg que nos grupos com 100 µg e controle (5, 3, 0, p = 0,048, respectivamente). Conclusão A administração intratecal de (S)-(+)-cetoprofeno causou alterações neuro-histopatológicas dose-dependentes em ratos nos dias 3 e 7 após a aplicação e sugerindo que o (S)-(+)-cetoprofeno não deve ser administrado por via intratecal.

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