Pain management & opioid dose reduction with topical sevoflurane instillations in intractable venous ulcers: a case report

Abstract Vascular ulcers (VU) constitute a major cause of pain and disability, and significantly compromise quality of life. VU have a natural tendency to become chronic and in many cases exhibit anunsatisfactoryresponse to many of the standard therapeutic options.The case of a 73 year-old Caucasian female with severe pain and poorly-controlled pain (Visual Analogic Scale-VAS- of 8-9) due to three lower leg long-standing VUs is reported and discussed herein. The patient was treated with topical instillations of undiluted sevoflurane as per institutional off-label protocol (starting doses of 1mL/cm2 twice a day, and up-titrated according to response to a maximum of 7 mL twice daily). The VAS score dropped to 0-1 shortly after initiation of therapy and remained stable throughout treatment up until the closure of the observations. Subsequently, opioid therapy was gradually tapered down and ultimately abandoned.Sevoflurane application resulted on adequate and sustained pain management of refractory VU, with no significant side effects. On account of its beneficial effectivity and safety profiles, topical sevoflurane emerges as an add-on alternative for the long-term management of VU, and potentially other painful conditions.

Coadministración de oxicodona y metadona para reducir la neurotoxicidad opioide y proveer analgesia: presentación de un caso / Co-administration of oxycodone and metadone to reduce central nervous system side-effects and provide analgesia: case report

Este artículo describe la coadministración de dos opioides agonistas en un paciente que padece dolor de origen oncológico, con la intención de disminuir la toxicidad opioide sobre el Sistema Nervioso Central y mantener un adecuado nivel de analgesia. La oxicodona y la metadona, usualmente utilizadas en humanos, son eficaces analgésicos alternativos de la morfina para tratar dolor moderado a severo. Está bien establecido que la oxicodona actúa sobre los receptores Mu y recientemente se determinó su acción sobre los receptores Kappa. La metadona, por el contrario, es agonista Mu y antagonista competitivo del receptor N-Metil-Di-Aspartato (NMDA). Cuando se los administra conjuntamente, se amplia el espectro de acción sobre diferentes receptores; esto permite disminuir la dosis de cada uno de ellos y contribuir así a revertir la neurotoxicidad opioide que presentaba el paciente. Sin embargo, es necesario realizar trabajos de investigación clínica controlados que avalen esta presunción teórica.

Effects of intrathecal L-and N-type calcium channel blockers on the antinociception evoked by opioid agonists in the rat tail flick test

The effects of intrathecal administration of nimodipine or omega-conotoxin GVIA(L- and N-type calcium channel blockers, respectively) alone or followed by DAMGO, DADLE or bremazocine (mu-, delta- and kappa- opioid agonists, respectively) were studied on the rat tail flick test. The N- (16 to 64 pmoles), but not the L-type blocker (60 to 240 pmoles) produced a dose and time-dependent increase in the latency for the tail-flick reflex. DAMGO (30 to 120 pmoles) or bremazocine (190 to 560 pmoles), but not DADLE (50 to 200 pmoles), produced a dose-dependent increase in the latency for the tail-flick reflex. The effect of the highest dose of DAMGO was smaller, while the effects of DADLE and bremazocine were not changed after nimodipine (60 pmoles). The effects of DADLE were significantly potentiated, while the effects of DAMGO and bremazocine were not changed after omega-conotoxin GVIA (16 pmoles). The intrathecal administration of an N-type calcium channel blocker with a delta-opioid agonist seems to be the most effective combination to produce antinociception in the rat tail flick test.