Scarparo H C, Maia R N, Filho Ea Dos Santos, Soares Ecs, Costa Fwg, Fonteles Csr, Bezerra T P, Ribeiro T R, Romero N R
Division of Clinical Pharmacology, Department of Clinical Dentistry, Federal University of Ceará, Ceará, Brazil.
Division of Oral and Maxillofacial Surgery, Oral and Maxillofacial Surgery Residency Program, Dr. José Frota Hospital Institute, Ceará, Brazil.
Aust Dent J. 2016 Dec;61(4):446-454. doi: 10.1111/adj.12410.
Local anaesthetic-related systemic toxicity mainly results from elevated plasma concentrations of these drugs. We hypothesized that intraoral injection of submaximal doses of mepivacaine does not lead to toxic levels of this drug in blood. This study evaluated the plasma levels of mepivacaine in third molars surgeries.
Twenty-one patients were randomly assigned into two groups: group I (two unilateral third molars; submaximal dose of mepivacaine 108 mg with epinephrine 54 μg) and group II (four third molars; submaximal dose of mepivacaine 216 mg with epinephrine 108 μg). Blood samples were collected before anaesthesia, and 5, 10, 15, 20, 30, 40, 60, 90 and 120 min after anaesthesia.
Individual peak plasma concentrations ranged 0.77-8.31 μg/mL (group I) and from 2.36-7.72 μg/mL (group II). An increase in the average dose of mepivacaine from 1.88 ± 0.12 mg/kg (group I) to 3.35 ± 0.17 mg/kg (group II) increased the mean mepivacaine peak plasma levels from 2.33 ± 0.58 to 4.01 ± 0.69 μg/mL, respectively. Four patients obtained plasma levels of mepivacaine above the threshold for toxicity (5 μg/mL).
Toxic levels of mepivacaine are possible, even when a submaximal dose is used. A twofold increase in the dose of mepivacaine caused the mean peak plasma concentration to increase proportionally, indicating that they may be predicted based on the relation of dose per bodyweight.
局部麻醉药相关的全身毒性主要源于这些药物血浆浓度的升高。我们推测，口腔内注射次最大剂量的甲哌卡因不会导致该药物在血液中达到中毒水平。本研究评估了第三磨牙手术中甲哌卡因的血浆水平。
21例患者被随机分为两组：第一组（两颗单侧第三磨牙；甲哌卡因次最大剂量108mg加肾上腺素54μg）和第二组（四颗第三磨牙；甲哌卡因次最大剂量216mg加肾上腺素108μg）。在麻醉前以及麻醉后5、10、15、20、30、40、60、90和120分钟采集血样。
个体血浆峰值浓度范围为0.77 - 8.31μg/mL（第一组）和2.36 - 7.72μg/mL（第二组）。甲哌卡因平均剂量从1.88±0.12mg/kg（第一组）增加到3.35±0.17mg/kg（第二组），分别使甲哌卡因平均血浆峰值水平从2.33±0.58μg/mL增加到4.01±0.69μg/mL。四名患者的甲哌卡因血浆水平超过了中毒阈值（5μg/mL）。
即使使用次最大剂量，甲哌卡因也有可能达到中毒水平。甲哌卡因剂量增加两倍导致平均血浆峰值浓度成比例增加，表明它们可能根据每体重剂量的关系进行预测。
