A Comparison of Proparacaine and Tetracaine Eye Anesthetics

Abstract

Objective: To compare two topical eye anesthetics, proparacaine and tetracaine, for pain of instillation and duration of activity.Methods: Volunteers received both anesthetics in a prospective, randomized, double-masked protocol. The subjects were given one drop of a study solution in the lower lid fornix of the left eye. Immediately after receiving the medication, they rated the pain of instillation on a previously validated visual-analog pain scale. This procedure was then repeated in the right eye with the other study solution. Pain scales were quantified by making measurements to the nearest millimeter from the point of scale origin to the point marked by the patient. The time interval until return of the corneal blink reflex was determined using a cotton wisp. Pain scores and the time to return of corneal reflex were analyzed by the Sign test and Wilcoxon rank-sum test, respectively, with significance defined as p < 0.05. Results:Twenty-three subjects were available for analysis. Twenty subjects reported proparacaine hurt less than tetracaine, two felt the pain was the same for the two agents, and only one reported that proparacaine was more painful. The mean pain score for tetracaine was 24 mm (100 mm maximum) higher than that for proparacaine (p < 0.0002). Proparacaine lasted 1.3 minutes longer than tetracaine, 10.7 minutes versus 9.4 minutes (p = 0.0001). Conclusion:Proparacaine eye drops cause less pain than tetracaine eye drops upon instillation. Anesthesia from proparacaine lasts slightly longer. These properties make proparacaine preferable to tetracaine.

Estudo clínico e histológico das pálpebras e conjuntiva hígidas submetidas ao tratamento tópico com soluções anestésicas em coelhos

“…2). Tais resultados estão de acordo com Bartfield et al (1994), Campos et al (1994) e Grant e Acosta (1994), que descreveram maior toxicidade do cloridrato de tetracaína quando comparado ao cloridrato de proparacaína.…”

“…O desconforto ocular não foi verificado em nenhum animal que recebeu colírio de proparacaína do presente experimento, assim como nas avaliações feitas por Bartfield et al (1994) e Marsh et al (2005.…”

“…Os colírios anestésicos desempenham papel de fundamental importância na oftalmologia humana e veterinária, sendo mais comumente utilizados o cloridrato de tetracaína e o cloridrato de proparacaína (Bartfield et al, 1994;Marsh et al, 2005). Manipulações simples para fins de diagnóstico, tais como a tonometria, a inspeção em busca de corpo estranho ocular, a inspeção da terceira pálpebra e do ducto nasolacrimal, seriam praticamente impossíveis sem a utilização desses fármacos.…”

“…O fármaco é apresentado na solução de 0,5%, e o tempo para início da anestesia é em torno de 13 segundos, perdurando por 15 minutos em média. (Bartfield et al, 1994;Campos et al, 1994;Grant e Acosta, 1994;Marcondes, 1999).…”

Cytotoxicity of proparacaine to human corneal endothelial cells <i>in vitro </i>

“…Proparacaine, with advantages of high efficiency and low side effect, is one of the most frequently used topical anesthetics in ophthalmic optometry and various kinds of surgery (Bartfield et al, 1994;Kiliç and Gürler, 2006). Prolonged and repeated use of proparacaine and the other topical anesthetics such as lidocaine, oxybuprocaine, bupivacaine and tetracaine were found to be cytotoxic to corneal endothelial cells in rabbit models (Chang et al, 2006;Judge et al, 1997).…”