Reversal of soft-tissue local anesthesia with phentolamine mesylate in adolescents and adults.

BACKGROUND: The authors conducted two multicenter, randomized, double-blinded, controlled Phase III clinical trials to study the efficacy and safety of phentolamine mesylate (PM) in shortening the duration and burden of soft-tissue anesthesia. The study involved 484 subjects who received one of four commercially available local anesthetic solutions containing vasoconstrictors for restorative or scaling procedures. METHODS: On completion of the dental procedure, subjects randomly received a PM or a sham injection (an injection in which a needle does not penetrate the soft tissue) in the same site as the local anesthetic injection. The investigators measured the duration of soft-tissue anesthesia by using standardized lip- and tongue-tapping procedures every five minutes for five hours. They also evaluated functional measures and subject-perceived altered function, sensation, appearance and safety. RESULTS: Median recovery times in the lower lip and tongue for subjects in the PM group were 70 minutes and 60 minutes, respectively. Median recovery times in the lower lip and tongue for subjects in the sham group were 155 minutes and 125 minutes, respectively. Upper lip median recovery times were 50 minutes for subjects in the PM group and 133 minutes for subjects in the sham group. These differences were significant (P < .0001). Recovery from actual functional deficits and subject-perceived altered function, sensation and appearance also showed significant differences between the PM and the sham groups. CONCLUSIONS: PM was efficacious and safe in reducing the duration of local anesthetic- induced soft-tissue numbness and its associated functional deficits. CLINICAL IMPLICATIONS: Clinicians can use PM to accelerate reversal of soft-tissue anesthesia and the associated functional deficits.

An inhibitory effect of polyphloretin phosphate (PPP) on local anaesthesia.

In the present investigation it is shown that administration of polyphloretin phosphate (PPP) together with local anaesthetics decreased the duration of infiltration anaesthesia in guinea-pigs. Furthermore, it is shown that in infiltration anaesthesias the local anaesthetic effect was terminated within a few minutes by administration of PPP. In experiments with high- and low-molecular fractions of PPP, the "anti-local anaesthetic" effect of PPP was not due to the antiprostaglandin activity of PPP. There was no effect of PPP on the duration of the nerve-blocking activity of mepivacaine in rats. Neither did the administration of PPP influence the toxic effects of mepivacaine in rabbits.