Experimental study of tetrodotoxin, a long-acting topical anesthetic - 09/09/11
Abstract |
Purpose |
To determine the effectiveness and toxicity of tetrodotoxin for use as a long-acting topical anesthetic.
Methods |
Four groups of six rabbits each received a 40-μl aliquot of either tetrodotoxin in one of three concentrations (10 mM, 1 mM, or 0.1 mM) or proparacaine 0.5% into the inferior conjunctival cul-de-sac of one eye, with the fellow eye of each rabbit receiving 40 μl of a 60-mM, pH 4.3 sodium citrate vehicle as a control. Corneal sensation was tested for up to 8 hours after administration of drugs, and response was noted by no blink, partial blink without full eyelid closure, and full blink. Slit-lamp examination at 12 and 24 hours after administration and pachymetry before and 24 hours after administration were performed to detect corneal toxicity.
Results |
Rabbits receiving all three concentrations of tetrodotoxin did not demonstrate any ocular irritation, corneal thickening, or signs of systemic toxicity. At a dose of 10 mM, tetrodotoxin produced an anesthetic effect lasting up to 8 hours. At 1 mM, tetrodotoxin was an effective but shorter-acting anesthetic. At 0.1 mM, tetrodotoxin had no significant anesthetic effect. Proparacaine-treated rabbits initially were anesthetic, but this effect was largely gone by 1 hour and completely gone by 3 hours.
Conclusions |
Tetrodotoxin is a long-acting topical anesthetic in the rabbit cornea. Although additional toxicity studies are required, tetrodotoxin may provide an effective, long-lasting topical anesthetic for use in pain control after corneal procedures such as photorefractive keratectomy.
Le texte complet de cet article est disponible en PDF.* | Supported in part by an unrestricted grant and core grant EY02162 from Research to Prevent Blindness, Inc, New York, New York. |
Vol 125 - N° 4
P. 481-487 - avril 1998 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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