Articles: anesthetics.
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Oral Surg. Oral Med. Oral Pathol. · Jun 1985
Drug interactions and vasoconstrictors used in local anesthetic solutions.
This study examined widely advertised interactions between sympathomimetic amine vasoconstrictors currently used in dental local anesthetic solutions and MAO inhibitors (phenelzine, 5 mg/kg), phenothiazines (chlorpromazine, 2 mg/kg), and tricyclic antidepressants (desipramine, 2 mg/kg). Twelve greyhound dogs premedicated with morphine and anesthetized with urethane and alpha-chloralose were prepared for physiologic recordings. During a control period, the dogs received bolus injections of epinephrine, norepinephrine, and levonordefrin sufficient to construct log-linear dose-response curves for each agent. ⋯ Cardiovascular responses were not influenced by the coadministration of local anesthetics or by the prior administration of phenelzine. Chlorpromazine ameliorated pressor responses to norepinephrine and levonordephrin and reversed the hypertensive effect of high-dose epinephrine. Desipramine significantly increased vasoconstrictor potencies, particularly those of levonordefrin and norepinephrine, which were multiplied more than sixfold.
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Acta Anaesthesiol Scand · May 1985
Effects of adjuvants to local anaesthetics on their duration. I. Studies of dextrans of widely varying molecular weight and adrenaline in rat infraorbital nerve block.
Local anaesthetics of the amide type were studied in a modified rat infraorbital nerve block model, with which it was possible to determine varying degrees of sensory block. Of the agents investigated, 0.5% bupivacaine tended to give a longer duration of block than 2% prilocaine or 2% lidocaine, while 0.5% etidocaine had the shortest duration. The duration of prilocaine was prolonged by addition of adrenaline, 5 micrograms/ml, more than that of the other agents. ⋯ The extent of prolongation was dependent on the degree of block, the concentration of dextrans in the local anaesthetic solution, and the Mw of the dextran although in a less uniform way. An increase in the relative viscosity of the solutions might be a factor of importance for the prolonging effect of addition of dextran to local anaesthetics. Since a formulation providing analgesia of a long duration would be of clinical value, further studies on combinations of the comparatively low-toxicity agent prilocaine and macromolecular substances are of interest.