Pro- and anticonvulsant effects of anesthetics (Part I)

摘要: Perioperative seizures have numerous potential etiologies. In general, when occur during surgery, their onset often coincides with the introduction of a specific anesthetic or analgesic drug. Conversely, postoperative are more commonly due to nonanesthetic causes. However, there been reports convulsions that appeared be caused by drugs administered intraoperatively via inhalation injection (e.g., intravenous, epidural, peripheral nerve block). Some anesthetics appear possess both proconvulsant and anticonvulsant properties. One possible factor is an inherent pharmacodynamic variability in responsiveness inhibitory excitatory target tissues CNS. This well illustrated effects progressively higher doses local drugs. neuronal could also explain conflicting findings for low versus high fentanyl etomidate. Furthermore, biological variation individual patient's certain additional contributory factor. Differing structure-activity relationships might why some agents Relatively minor modifications drug's structure can influence its affinity receptor site intrinsic pharmacologic activity. For example, methohexital was first introduced, were encountered patients without history epilepsy. Subsequent fractionation original compound into two isomeric forms resulted identification isomer primarily responsible this convulsive present formulation (Brevital; Eli Lilly, Indianapolis, Ind.), epileptogenic properties limited psychomotor compared thiopental, still common methohexital. The presumably methylated structure. inhaled flurothyl (hexaflurodiethyl) ether intravenous ketamine illustrate how subtle changes stereoisomerism result significant relationships. Flurothyl, fluorinated analogue, reliably produces nonepileptic patients, whereas structural isoindoklon has not associated seizure Other examples analogue produce differential on hyperexcitability include enflurane-isoflurane meperidine-normeperidine. conclusion, patient population (epileptic nonepileptic), method documentation (EEG study clinical observation), EEG analysis (cortical depth electrodes) must considered properly analyze and/or drug.(ABSTRACT TRUNCATED AT 400 WORDS)