RESUMO
Purpose: This study aimed to determine the onset and duration of action of 3 commercially available topical anesthetic solutions in Brazil, using the Cochet-Bonnet esthesiometer (Luneau®, Paris, France) and to quantitatively assess patient-reported discomfort during application. Methods: A prospective, randomized, masked, and double-blind study was conducted, involving 40 eyes from 21 patients. Patients were administered each one of the topical anesthetics weekly, and corneal sensitivity was measured using the Cochet-Bonnet esthesiometer's corneal touch threshold (CTT). Patients rated the burning sensation using a visual analogue scale (VAS). Results: Among the 21 patients (42.9% male), with a mean age of 31.95 years (±standard deviation = 10.17, range = 22.0-58.0), corneal sensitivity significantly decreased 30 s after application, returning to baseline after 30 min for all groups (P < 0.0001). Significant differences in CTT were observed at 5 min, with proparacaine exhibiting a superior anesthetic effect (P = 0.0003), at 10 min, where tetracaine displayed the most substantial anesthetic effect (P = 0.0135), and at 20 min, where tetracaine demonstrated the highest anesthetic efficacy (P < 0.0001). VAS scores indicated the most intense burning sensation with tetracaine (P < 0.0001). Men reported experiencing more discomfort during instillation compared with women (P = 0.0168). Conclusions: Proparacaine exhibited the fastest onset of action among the 3 topical anesthetics and provided a more comfortable eye sensation during instillation. However, tetracaine demonstrated the longest duration of action despite causing more discomfort.
Assuntos
Anestésicos Locais , Córnea , Procaína , Propoxicaína , Tetracaína , Humanos , Masculino , Feminino , Tetracaína/administração & dosagem , Tetracaína/farmacologia , Adulto , Método Duplo-Cego , Propoxicaína/administração & dosagem , Propoxicaína/farmacologia , Anestésicos Locais/administração & dosagem , Anestésicos Locais/farmacologia , Pessoa de Meia-Idade , Estudos Prospectivos , Córnea/efeitos dos fármacos , Procaína/administração & dosagem , Procaína/farmacologia , Procaína/análogos & derivados , Procaína/efeitos adversos , Adulto Jovem , Soluções Oftálmicas/administração & dosagem , Medição da Dor/métodosRESUMO
Abstract Purpose: To assess the non-invasive tear break-up time (NITBUT) and tear meniscus height (TMH) after instilling the three different types of anesthetic eye drops by Oculus Keratograph 5M. Methods: In this prospective study, 85 healthy subjects (85 eyes) were randomly divided into three groups. The groups were randomly received lidocaine hydrochloride 2%, proparacaine hydrochloride 0.5%, and tetracaine hydrochloride 0.5%. The qualitative and quantitative parameters of tear film were assessed using NITBUT and TMH, respectively. In all groups, the quantity of tear film using TMH was measured in the right eye of subjects, while the quality of tear film using NITBUT was assessed in the left eye. The analysis of variance (ANOVA) was used to compare the difference between before and after the intervention. A P-value < 0.05 was considered significant. Results: Differences for TMH and NITBUT between before and after applying lidocaine hydrochloride 2% were not statistically significant (P > 0.05). The mean values of NITBUT and TMH after the instillation of proparacaine hydrochloride 0.5% showed a significant decrease than before the intervention (P < 0.05). Also, after the use of tetracaine hydrochloride 0.5%, the mean value of NITBUT was significantly increased (P < 0.05), but the mean value of TMH was significantly decreased than before the intervention (P < 0.05). Conclusion: Our study showed that lidocaine hydrochloride 2% as an anesthetic eye drops can be an appropriate choice for eye examinations due to a lack of significant effect on the quantity and quality of tear film.
Resumo Objetivo: Avaliar o tempo de ruptura lacrimal não invasivo (NITBUT) e a altura do menisco lacrimal (TMH) após instilar os três tipos diferentes de colírio anestésico pelo Oculus Keratograph 5M. Métodos: Neste estudo prospectivo, 85 indivíduos saudáveis (85 olhos) foram divididos aleatoriamente em três grupos. Os grupos receberam aleatoriamente cloridrato de lidocaína a 2%, cloridrato de proparacaína a 0.5% e cloridrato de tetracaína a 0.5%. Os parâmetros qualitativos e quantitativos do filme lacrimal foram avaliados utilizando NITBUT e TMH, respectivamente. Em todos os grupos, a quantidade de filme lacrimal utilizando TMH foi medida no olho direito dos sujeitos, enquanto a qualidade do filme lacrimal usando NITBUT foi avaliada no olho esquerdo. A análise de variância (ANOVA) foi utilizada para comparar a diferença entre antes e depois da intervenção. Um valor de P < 0.05 foi considerado significativo. Resultados: Diferenças para TMH e NITBUT entre antes e depois da aplicação de cloridrato de lidocaína a 2% não foram estatisticamente significantes (P > 0.05). Os valores médios de NITBUT e TMH após a instilação de cloridrato de proparacaína a 0.5% mostraram uma diminuição significativa do que antes da intervenção (P < 0.05). Além disso, após o uso de cloridrato de tetracaína a 0.5%, o valor médio de NITBUT foi significativamente aumentado (P < 0.05), mas o valor médio de TMH foi significativamente menor do que antes da intervenção (P < 0.05). Conclusão: Nosso estudo mostrou que o cloridrato de lidocaína a 2% como colírio anestésico pode ser uma escolha apropriada para exames oftalmológicos devido à falta de efeito significativo sobre a quantidade e a qualidade do filme lacrimal.
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Soluções Oftálmicas , Propoxicaína/farmacologia , Lágrimas/efeitos dos fármacos , Tetracaína/farmacologia , Topografia da Córnea/instrumentação , Anestésicos Locais/farmacologia , Lidocaína/farmacologia , Propoxicaína/administração & dosagem , Lágrimas/diagnóstico por imagem , Tetracaína/administração & dosagem , Estudos Prospectivos , Córnea/anatomia & histologia , Topografia da Córnea/métodos , Técnicas de Diagnóstico Oftalmológico/instrumentação , Anestésicos Locais/administração & dosagem , Lidocaína/administração & dosagemRESUMO
Experimental results indicate a significant decrease in the potential difference (PD) and in the short-circuit current (Isc) after the application of proparacaine to isolated toad skin, which may reflect an inhibition of the active transport of ions. This finding was explained on the basis of the results obtained from membrane models incubated with proparacaine. These consisted of human erythrocytes, isolated unsealed human erythrocyte membranes (IUM), phospholipid multilayers built-up of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylethanolamine (DMPE), representatives of phospholipid classes located in the outer and inner monolayers of the human erythrocyte membrane, respectively, and in large unilamellar vesicles (LUV) of DMPC X-ray diffraction showed that proparacaine interaction with DMPC and DMPE bilayers perturbed both structures, especially DMPC. This result, confirmed by fluorescence spectroscopy of DMPC LUV at 18 degrees C, demonstrated that the local anesthetic (LA) could interact with the lipid moiety of cell membranes. However, effects observed by scanning electron microscopy (SEM) of human erythrocytes and by fluorescence spectroscopy of IUM might also imply proparacaine-protein interactions. Thus, the LA may alter epitheial sodium channels through interaction with the lipid matrix and with channel protein residues.
Assuntos
Anestésicos Locais/farmacologia , Membrana Celular/ultraestrutura , Eritrócitos/ultraestrutura , Propoxicaína/farmacologia , Pele/metabolismo , Sódio/metabolismo , Animais , Anuros , Transporte Biológico/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/fisiologia , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/ultraestrutura , Eritrócitos/efeitos dos fármacos , Isomerismo , Bicamadas Lipídicas/química , Microscopia Eletrônica de Varredura , Pele/efeitos dos fármacos , Fenômenos Fisiológicos da PeleRESUMO
PURPOSE: To investigate the antibacterial activity of topical anesthetic solutions and their preservatives individually in vitro, to determine involvement with bacterial growth inhibition. MATERIAL AND METHODS: Proparacaine and tetracaine (in concentrations of 0.125%, 0.25%, and 0.50%), edetate disodium (EDTA), benzalkonium chloride, EDTA + benzalkonium chloride, and sterile saline solution were used. Five microliters of each solution were applied to standard filter paper disks and placed in Mueller-Hinton agar previously inoculated with known strains of Pseudomonas aeruginosa and Staphylococcus aureus. Zones of growth inhibition were measured 24 hours later and analyzed. RESULTS: There were no zones of inhibition in the agar inoculated with P. aeruginosa to all tested solutions. Benzalkonium chloride alone and associated with EDTA inhibited growth of S. aureus. All other solutions did not inhibit S. aureus. CONCLUSION: Preservative-free anesthetic solutions seemed not to interfere with bacterial development in culture media. Benzalkonium chloride alone and associated with EDTA inhibited development of gram positive bacteria, S. aureus, but did not inhibit P. aeruginosa.