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A N, Sahu L, Das S, Muni M. Comparative Evaluation of Dexmedetomidine and Dexamethasone as Adjuvants in Supraclavicular Brachial Plexus Block. Cureus 2023; 15:e38775. [PMID: 37303417 PMCID: PMC10249913 DOI: 10.7759/cureus.38775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2023] [Indexed: 06/13/2023] Open
Abstract
Introduction Currently, peripheral nerve block has shown immense potential with effective patient satisfaction. In the event of upper limb surgeries, the supraclavicular brachial plexus approach under ultrasound guidance renders quick and dense anesthesia. In addition, the clinical utility of adjuvants with local anesthetics elicits a good quality of nerve block with improved duration and inset. So the aim of the present study was to compare the block characteristics of dexmedetomidine and dexamethasone during supraclavicular brachial plexus block in patients undergoing upper limb surgeries. Materials and methods The present study was conducted on 100 patients aged 20-60 years with the American Society of Anesthesiologists (ASA)-I and ASA-II classification who were scheduled for upper limb surgeries. These patients were divided equally into two groups, namely group D (who received 20mL of 0.5% bupivacaine + 50 mcg (0.5mL) of dexmedetomidine +1.5mL normal saline) and group X (who received 20mL of 0.5% bupivacaine +8mg of dexamethasone), ensuring a total volume of 22mL administered to both groups. The time of onset and duration of the sensory and motor blocks, as well as the quality of intraoperative analgesia, were assessed. Results The addition of dexmedetomidine (50mcg) and dexamethasone (8mg) to 0.5% bupivacaine ensured a faster onset and prolonged duration of the sensory and motor blocks. Additionally, dexmedetomidine resulted in more prolonged postoperative analgesia, a lower mean visual analog scale score in the first 24 hours, and lesser opioid consumption in 24 hours than dexamethasone. Conclusion Dexmedetomidine is superior to dexamethasone as an adjuvant to bupivacaine during supraclavicular brachial plexus block in patients undergoing upper limb surgeries.
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Affiliation(s)
- Nagaraju A
- Anesthesiology, Employee's State Insurance Corporation (ESIC) Medical College and Hospital, Hyderabad, IND
| | - Lingaraj Sahu
- Anesthesia, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - Sudeepa Das
- Anatomy, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
| | - Manoja Muni
- Anesthesia, Kalinga Institute of Medical Sciences, Bhubaneswar, IND
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Prolonged Duration Local Anesthesia Using Liposomal Bupivacaine Combined With Liposomal Dexamethasone and Dexmedetomidine. Anesth Analg 2019; 126:1170-1175. [PMID: 29239940 DOI: 10.1213/ane.0000000000002719] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The relatively short duration of effect of local anesthetics has been addressed by encapsulation in drug delivery systems. Codelivery with a single compound that produces an adjuvant effect on nerve block but without intrinsic local anesthetic properties can further prolong the nerve block effect. Here, we investigated whether codelivery of more than 1 encapsulated adjuvant compound can further enhance nerve blockade. METHODS Liposomes loaded with bupivacaine (Bup), dexamethasone phosphate (DexP), or dexmedetomidine (DMED) were synthesized and its in vitro drug release profiles were determined. Animals (Sprague-Dawley rats) were injected with liposomal Bup (Lipo-Bup) and adjuvants at the sciatic nerve and underwent a modified hot plate test to assess the degree of nerve block. The duration of block was monitored and the tissue reaction was assessed. RESULTS Coinjection of Lipo-Bup with liposomal DexP (Lipo-DexP) and liposomal DMED (Lipo-DMED) prolonged the duration of sciatic nerve block 2.9-fold compared to Lipo-Bup alone (95% confidence interval, 1.9- to 3.9-fold). The duration of the block using this combination was significantly increased to 16.2 ± 3.5 hours compared to Lipo-Bup with a single liposomal adjuvant (8.7 ± 2.4 hours with Lipo-DMED, P = .006 and 9.9 ± 5.9 hours with Lipo-DexP, P = .008). The coinjection of Lipo-Bup with liposomal adjuvants decreased tissue inflammation (P = .014) but did not have a significant effect on myotoxicity when compared to Lipo-Bup alone. Coinjection of Lipo-Bup with unencapsulated adjuvants prolonged the duration of nerve block as well (25.0 ± 6.3 hours; P < .001) however was accompanied by systemic side effects. CONCLUSIONS Codelivery of Lipo-DexP and Lipo-DMED enhanced the efficacy of Lipo-Bup. This benefit was also seen with codelivery of both adjuvant molecules in the unencapsulated state, but with marked systemic toxicity.
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Addressing the Issue of Tetrodotoxin Targeting. Mar Drugs 2018; 16:md16100352. [PMID: 30261623 PMCID: PMC6212850 DOI: 10.3390/md16100352] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 12/27/2022] Open
Abstract
This review is devoted to the medical application of tetrodotoxin (TTX), a potent non-protein specific blocker of voltage-gated sodium (NaV) channels. The selectivity of action, lack of affinity with the heart muscle NaV channels, and the inability to penetrate the blood–brain barrier make this toxin an attractive candidate for anesthetic and analgesic drug design. The efficacy of TTX was shown in neuropathic, acute and inflammatory pain models. The main emphasis of the review is on studies focused on the improvement of TTX efficacy and safety in conjunction with additional substances and drug delivery systems. A significant improvement in the effectiveness of the toxin was demonstrated when used in tandem with vasoconstrictors, local anesthetics and chemical permeation enhancers, with the best results obtained with the encapsulation of TTX in microparticles and liposomes conjugated to gold nanorods.
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Yu J, Shan S, Nie Y. Impact of local administration of various doses of dexmedetomidine on ropivacaine-induced lumbar plexus-sciatic nerve block. Exp Ther Med 2018; 16:711-717. [PMID: 30116325 PMCID: PMC6090230 DOI: 10.3892/etm.2018.6218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 12/15/2017] [Indexed: 11/24/2022] Open
Abstract
The present study aimed to investigate the impact of various doses of dexmedetomidine (DEX) on ropivacaine (ROP)-induced lumbar plexus-sciatic nerve block (LSB). A total of 80 patients who underwent ankle surgery under LSB were divided into group R (applied with 30 ml 5% ROP), Dex1 (30 ml 0.5% ROP + 1 µg/kg DEX), Dex2 (30 ml 0.5% ROP + 1.5 µg/kg DEX) and Dex3 (30 ml 0.5% ROP + 2 µg/kg DEX), with 20 cases in each group. The onset time and duration of sensory and motor block, mean arterial pressure (MAP), heart rate (HR), oxygen saturation, Ramsay score, serum vascular endothelial growth factor (VEGF) level and adverse reactions in the four groups were observed. Results demonstrated that the durations of sensory and motor block in group R were shorter than those in groups Dex1-3 (P<0.01), followed by the sequence of group Dex1<Dex2<Dex3 (P<0.05). MAP and HR in groups Dex1-3 at T2-T5 were significantly lower than those in group R (P<0.01), and HR in group Dex3 at T3 and T4 was significantly lower than that in groups Dex1 and Dex2 (P<0.05). Ramsay scores in groups Dex1-3 at T2-T4 were significantly higher than those in group R (P<0.05). Serum VEGF levels in groups Dex2 and Dex3 at T2-T5 were significantly higher than those in group R (P<0.01). The incidences of over-sedation, bradycardia and dry mouth in group Dex3 were notably higher than those in the other groups. In conclusion, 1.5 µg/kg DEX exhibits a superior effect in improving ROP-induced LSB.
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Affiliation(s)
- Jian Yu
- Department of Anesthesiology, Central Hospital of Cangzhou, Cangzhou, Hebei 061000, P.R. China
| | - Shiqiang Shan
- Department of Anesthesiology, Central Hospital of Cangzhou, Cangzhou, Hebei 061000, P.R. China
| | - Yu Nie
- Department of Anesthesiology, Central Hospital of Cangzhou, Cangzhou, Hebei 061000, P.R. China
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Rwei AY, Paris JL, Wang B, Wang W, Axon CD, Vallet-Regí M, Langer R, Kohane DS. Ultrasound-triggered local anaesthesia. Nat Biomed Eng 2017; 1:644-653. [PMID: 29152410 PMCID: PMC5687284 DOI: 10.1038/s41551-017-0117-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 06/27/2017] [Indexed: 01/09/2023]
Abstract
On-demand relief of local pain would allow patients to control the timing, intensity and duration of nerve block in a safe and non-invasive manner. Ultrasound would be a suitable trigger for such a system, as it is in common clinical use and can penetrate deeply into the body. Here, we demonstrate that ultrasound-triggered delivery of an anaesthetic from liposomes allows the timing, intensity and duration of nerve block to be controlled by ultrasound parameters. On insonation, the encapsulated sonosensitizer protoporphyrin IX produces reactive oxygen species that react with the liposomal membrane, leading to the release of the potent local anaesthetic tetrodotoxin. We also show repeatable ultrasound-triggered nerve blocks in vivo, with nerve-block duration depending on the extent and intensity of insonation. We did not detect any systemic toxicity, and tissue reaction was benign in all groups. On-demand, personalized local anaesthesia could be beneficial for the managing of relatively localized pain states, and potentially minimize opioid use.
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Affiliation(s)
- Alina Y Rwei
- Department of Anaesthesiology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Juan L Paris
- Dpto. Química Inorgánica y Bioinorgánica, Facultad de Farmacia, UCM, Instituto de Investigación Sanitaria Hospital 12 de Octubre i+12, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Avenida Monforte de Lemos, 3-5, 28029, Madrid, Spain
| | - Bruce Wang
- Department of Anaesthesiology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Weiping Wang
- Dr Li Dak-Sum Research Centre, The University of Hong Kong-Karolinska Institutet Collaboration in Regenerative Medicine, The University of Hong Kong, Hong Kong, China
| | - Christopher D Axon
- Department of Anaesthesiology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - María Vallet-Regí
- Dpto. Química Inorgánica y Bioinorgánica, Facultad de Farmacia, UCM, Instituto de Investigación Sanitaria Hospital 12 de Octubre i+12, 28040, Madrid, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Avenida Monforte de Lemos, 3-5, 28029, Madrid, Spain
| | - Robert Langer
- David H. Koch Institutes for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Daniel S Kohane
- Department of Anaesthesiology, Boston Children's Hospital, Boston, MA, 02115, USA.
- Laboratory for Biomaterials and Drug Delivery, Harvard Medical School, Boston, MA, 02115, USA.
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Santamaria CM, Zhan C, McAlvin B, Zurakowski D, Kohane DS. Tetrodotoxin, Epinephrine, and Chemical Permeation Enhancer Combinations in Peripheral Nerve Blockade. Anesth Analg 2017; 124:1804-1812. [PMID: 28452816 PMCID: PMC5438287 DOI: 10.1213/ane.0000000000002072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Chemical permeation enhancers (CPEs) have the potential to improve nerve blockade by site 1 sodium channel blockers such as tetrodotoxin (TTX). Here, we investigated the efficacy and toxicity of CPE-enhanced nerve blockade across a range of TTX concentrations using 2 CPEs (sodium octyl sulfate and octyl trimethyl ammonium bromide). We also tested the hypothesis that CPEs could be used to reduce the concentrations of TTX and/or of a second adjuvant drug (in this case, epinephrine) needed to achieve prolonged local anesthesia METHODS:: Sprague-Dawley rats were injected at the sciatic nerve with combinations of TTX and CPEs, with and without epinephrine. Sensory and motor nerve blockade were assessed using a modified hot plate test and a weight-bearing test, respectively. Systemic and local toxicities of the different combinations were assessed. RESULTS Addition of increasing concentrations of TTX to fixed concentrations of CPEs produced a marked concentration-dependent improvement in the rate of successful nerve blocks and in nerve block duration. CPEs did not affect systemic toxicity. At some concentrations, the addition of sodium octyl sulfate increased the duration of block from TTX plus epinephrine, and epinephrine increased that from TTX plus CPEs. The addition of epinephrine did not cause an increase in local toxicity, and it markedly reduced systemic toxicity. CONCLUSIONS CPEs can prolong the duration of nerve blockade across a range of concentrations of TTX. CPEs could also be used to reduce the concentration of epinephrine needed to achieve a given degree of nerve block. CPEs may be useful in enhancing nerve blockade from site 1 sodium channel blockers.
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Affiliation(s)
- Claudia M. Santamaria
- Laboratory for Biomaterials and Drug Delivery, Division of Critical Care Medicine, Department of Anesthesiology, Boston Children’s Hospital, Boston, MA, United States
| | - Changyou Zhan
- Laboratory for Biomaterials and Drug Delivery, Division of Critical Care Medicine, Department of Anesthesiology, Boston Children’s Hospital, Boston, MA, United States
| | - Brian McAlvin
- Laboratory for Biomaterials and Drug Delivery, Division of Critical Care Medicine, Department of Anesthesiology, Boston Children’s Hospital, Boston, MA, United States
- Division of Medicine Critical Care, Department of Medicine, Boston Children’s Hospital, Boston, MA, United States
| | - David Zurakowski
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital, Boston, MA, United States
| | - Daniel S. Kohane
- Laboratory for Biomaterials and Drug Delivery, Division of Critical Care Medicine, Department of Anesthesiology, Boston Children’s Hospital, Boston, MA, United States
- Department of Anesthesiology, Perioperative, and Pain Medicine, Boston Children’s Hospital, Boston, MA, United States
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Rwei AY, Zhan C, Wang B, Kohane DS. Multiply repeatable and adjustable on-demand phototriggered local anesthesia. J Control Release 2017; 251:68-74. [PMID: 28153763 PMCID: PMC5394744 DOI: 10.1016/j.jconrel.2017.01.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/29/2016] [Accepted: 01/26/2017] [Indexed: 11/18/2022]
Abstract
A phototriggerable system whereby patients could repeatedly and non-invasively control the timing and dosage of local anesthesia according to their needs would be beneficial for perioperative pain and perhaps obviate the need for oral narcotics. However, clinical application of phototriggerable systems have been limited by concerns over phototoxicity of lasers and limited tissue penetration of light. To address these limitations, we increased the devices' effective sensitivity to light by co-delivering a second compound, dexmedetomidine, that potentiates the effect of delivered local anesthetics. The concurrent release of dexmedetomidine enhanced the efficacy of released local anesthetics, greatly increasing the number of triggerable nerve blocks (up to nine triggerable events upon a single injection) and reducing the irradiance needed to induce nerve block by 94%. The intensity and duration of on-demand analgesia could be adjusted by varying the intensity and duration of irradiance, which could not only be delivered by lasers, but also by light-emitting diodes, which are less expensive, safer, and more portable.
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Affiliation(s)
- Alina Y Rwei
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Changyou Zhan
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bruce Wang
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Daniel S Kohane
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Bisui B, Samanta S, Ghoshmaulik S, Banerjee A, Ghosh TR, Sarkar S. Effect of Locally Administered Dexmedetomidine as Adjuvant to Levobupivacaine in Supraclavicular Brachial Plexus Block: Double-blind Controlled Study. Anesth Essays Res 2017; 11:981-986. [PMID: 29284860 PMCID: PMC5735499 DOI: 10.4103/aer.aer_55_17] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Context Brachial plexus block is effective with good postoperative analgesia in upper limb surgery has gained importance as it safe, low cost, and maintains stable hemodynamics intraoperatively. To decrease the onset time and prolong the duration of nerve block bicarbonate, opioids (morphine, fentanyl, etc.), sympathomimetic agents (epinephrine, phenylephrine, etc.), α-2 agonists (clonidine and dexmedetomidine), calcium channel blocker (verapamil), magnesium sulfate, etc., were studied with local anesthetics and their isomers. For their sedative, analgesic, perioperative sympatholytic, and cardiovascular stabilizing effects with reduced anesthetic requirements, α-2 adrenergic receptor agonists, such as more potent and highly selective dexmedetomidine, have been the focus of interest for regional anesthesia. Intravenous dexmedetomidine infusion resulted in significant opioid-sparing effects as well as a decrease in inhalational anesthetic requirements. Animal studies proved that dexmedetomidine enhances sensory and motor blockade along with increased duration of analgesia. In humans, dexmedetomidine has also shown to prolong the duration of block and postoperative analgesia when added to local anesthetic in various regional blocks. Bupivacaine, the widely used local anesthetic in regional anesthesia, is available in a commercial preparation as a racemic mixture (50:50) of its two enantiomers: levobupivacaine, S (-) isomer and dextrobupivacaine, R (+) isomer. Severe central nervous system and cardiovascular adverse reactions reported in the literature after inadvertent intravascular injection or intravenous regional anesthesia have been linked to the R (+) isomer of bupivacaine. The levorotatory isomers were shown to have a safer pharmacological profile with less cardiac and neurotoxic adverse effects. The decreased toxicity of levobupivacaine is attributed to its faster protein binding rate. The pure S (-) enantiomers of bupivacaine, i.e., ropivacaine and levobupivacaine were thus introduced into the clinical anesthesia practice. Such an increased usage mandates the documentation of evidence-based literature with regard to risk and safety concerns as well as clinical issues related to levobupivacaine. This study is designed to assess the efficacy of adding dexmedetomidine to levobupivacaine during placement of supraclavicular brachial plexus blockade. Materials and Methods This prospective observational double-blinded study was conducted over a 1-year period among randomly selected seventy (n = 35) American Society of Anesthesiologists Classes I and II patients of ages between 18 and 60 years of both sexes scheduled to undergo upper limb surgery. With nerve locator, levobupivacaine (0.5%) 28 ml and 2 ml normal saline for Group L and levobupivacaine (0.5%) 28 ml and 0.75 μg/kg dexmedetomidine made up a solution of 2 ml, for Group D, a total 30 ml will be injected locally, in both the groups. Onset and duration of sensory and motor block will be assessed. Results and Discussion One patient in Group L and two patients in Group D failed to achieve block within 30 min. Those three patients were then excluded from the analysis. Hence, the analysis was done by taking 34 patients in Group L and 33 patients in Group D. Onset of sensory and motor block was earlier in Group D (12.03 ± 0.85 and 13.58 ± 0.97) than Group L (14.32 ± 1.15 and 15 ± 0.98), and the difference is statistically significant (P < 0.0001). Duration of sensory and motor block was longer in Group D (563.94 ± 15.60 and 495.15 ± 10.34) than Group L (368.53 ± 9.89 and 321.47 ± 7.84), and the difference is also statistically significant (P < 0.0001). Duration of analgesia was longer in Group D (672.12 ± 11.39) than Group L (506.47 ± 9.497), and the difference is statistically significant (P < 0.0001). Heart rate and mean arterial pressure were well maintained within the presumed range of significant variation, i.e., 20% from baseline, though at some point of time, intergroup comparison was statistically significant. Visual analog scale score compared at the time for administration of rescue analgesic between the groups come out to be statistically significant. Conclusion Addition of 0.75 μg/kg dexmedetomidine to 0.5% levobupivacaine for supraclavicular plexus block shortens sensory and motor block onset time and extends sensory block, motor block, and analgesia duration.
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Affiliation(s)
- Bikash Bisui
- Department of Anaesthesiology and Critical Care, BS Medical College, Bankura, West Bengal, India
| | - Swastika Samanta
- Department of Anaesthesiology and Critical Care, Burdwan Medical College and Hospital, Burdwan, West Bengal, India
| | - Sumanta Ghoshmaulik
- Department of Anaesthesiology and Critical Care, Burdwan Medical College and Hospital, Burdwan, West Bengal, India
| | - Amit Banerjee
- Department of Anaesthesiology and Critical Care, Burdwan Medical College and Hospital, Burdwan, West Bengal, India
| | - Tirtha R Ghosh
- Department of Anaesthesiology and Critical Care, BS Medical College, Bankura, West Bengal, India
| | - Suman Sarkar
- Department of Anaesthesiology and Critical Care, BS Medical College, Bankura, West Bengal, India
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McAlvin JB, Zhan C, Dohlman JC, Kolovou PE, Salvador-Culla B, Kohane DS. Corneal Anesthesia With Site 1 Sodium Channel Blockers and Dexmedetomidine. Invest Ophthalmol Vis Sci 2015; 56:3820-6. [PMID: 26066750 DOI: 10.1167/iovs.15-16591] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Amino-amide or amino-ester local anesthetics, which are currently used for topical ocular anesthesia, are short acting and may delay corneal healing with long-term use. In contrast, site 1 sodium channel blockers (S1SCBs) are potent local anesthetics with minimal adverse tissue reaction. In this study, we examined topical local anesthesia with two S1SCBs, tetrodotoxin (TTX) or saxitoxin (STX) individually or in combination with α2-adrenergic receptor agonists (dexmedetomidine or clonidine), and compared them with the amino-ester ocular anesthetic proparacaine. The effect of test solutions on corneal healing was also studied. METHODS Solutions of TTX ± dexmedetomidine, TTX ± clonidine, STX ± dexmedetomidine, dexmedetomidine, or proparacaine were applied to the rat cornea. Tactile sensitivity was measured by recording the blink response to probing of the cornea with a Cochet-Bonnet esthesiometer. The duration of corneal anesthesia was calculated. Cytotoxicity from anesthetic solutions was measured in vitro. The effect on corneal healing was measured in vivo after corneal debridement followed by repeated drug administration. RESULTS Addition of dexmedetomidine to TTX or STX significantly prolonged corneal anesthesia beyond that of either drug alone, whereas clonidine did not. Tetrodotoxin or STX coadministered with dexmedetomidine resulted in two to three times longer corneal anesthesia than did proparacaine. S1SCB-dexmedetomidine formulations were not cytotoxic. Corneal healing was not delayed significantly by any of the test solutions. CONCLUSIONS Coadministration of S1SCBs with dexmedetomidine provided prolonged corneal anesthesia without delaying corneal wound healing. Such formulations may be useful for the management of acute surgical and nonsurgical corneal pain.
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Affiliation(s)
- James Brian McAlvin
- Department of Medicine Division of Medicine Critical Care, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, United States 2Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Med
| | - Changyou Zhan
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Jenny C Dohlman
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Paraskevi E Kolovou
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Borja Salvador-Culla
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, United States 3Department of Ophthalmology, Schepens Eye Research I
| | - Daniel S Kohane
- Laboratory for Biomaterials and Drug Delivery, Department of Anesthesiology, Division of Critical Care Medicine, Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts, United States
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McAlvin JB, Kohane DS. Prolonged Duration Local Anesthesia. ADVANCES IN DELIVERY SCIENCE AND TECHNOLOGY 2014. [DOI: 10.1007/978-1-4614-9434-8_28] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Duration and local toxicity of sciatic nerve blockade with coinjected site 1 sodium-channel blockers and quaternary lidocaine derivatives. Reg Anesth Pain Med 2013; 37:483-9. [PMID: 22914659 DOI: 10.1097/aap.0b013e31826125b3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND AND OBJECTIVES Quaternary lidocaine derivatives (QLDs) have recently received much attention because of their potential application in prolonged or sensory-selective local anesthesia. However, associated tissue toxicity is an impeding factor that makes QLDs unfavorable for clinical use. Based on the proposed intracellular site of action, we hypothesized that nerve blocks obtained from lower concentrations of QLDs would be enhanced by the coapplication of extracellularly acting site 1 sodium-channel blocker, resulting in prolonged block duration but with minimal tissue toxicity. METHODS Quaternary lidocaine derivatives (QX-314 or QX-222), site 1 sodium-channel blockers (tetrodotoxin [30 μM] or saxitoxin [12.5 μM]), or both were injected in the vicinity of the sciatic nerve. Thermal nociceptive block was assessed using a modified hot plate test; motor block by a weight-bearing test. Tissue from the site of injection was harvested for histological assessment. RESULTS Coapplication of 25 mM QX-314 or 100 mM QX-222 with site 1 sodium-channel blockers produced an 8- to 10- fold increase in the duration of nerve blocks (P < 0.05), compared with QLDs or site 1 blockers alone. Quaternary lidocaine derivatives elicited severe myotoxicity; this was not exacerbated by coinjection of the site 1 sodium-channel blockers. CONCLUSIONS Coadministration of site 1 sodium-channel blockers and QLDs greatly prolongs the duration of peripheral nerve block without enhancing local tissue injury, but minimal myotoxicity still persists. It is not clear that the risks of QLDs are outweighed by the benefits in providing prolonged nerve blockade.
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Abstract
Injectable local anesthetics that would last for many days could have a marked impact on periprocedural care and pain management. Formulations have often been limited in duration of action, or by systemic toxicity, local tissue toxicity from local anesthetics, and inflammation. To address those issues, we developed liposomal formulations of saxitoxin (STX), a compound with ultrapotent local anesthetic properties but little or no cytotoxicity. In vitro, the release of bupivacaine and STX from liposomes depended on the lipid composition and on whether dexamethasone was incorporated. In cell culture, bupivacaine, but not STX, was myotoxic (to C2C12 cells) and neurotoxic (to PC12 cells) in a concentration- and time-dependent manner. Liposomal formulations containing combinations of the above compounds produced sciatic nerve blockade lasting up to 7.5 days (with STX + dexamethasone liposomes) in male Sprague-Dawley rats. Systemic toxicity only occurred where high loadings of dexamethasone increased the release of liposomal STX. Mild myotoxicity was only seen in formulations containing bupivacaine. There was no nerve injury on Epon-embedded sections, and these liposomes did not up-regulate the expression of 4 genes associated with nerve injury in the dorsal root ganglia. These results suggest that controlled release of STX and similar compounds can provide very prolonged nerve blocks with minimal systemic and local toxicity.
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Simons EJ, Bellas E, Lawlor MW, Kohane DS. Effect of chemical permeation enhancers on nerve blockade. Mol Pharm 2009; 6:265-73. [PMID: 19105721 DOI: 10.1021/mp800167a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical permeation enhancers (CPEs) have the potential to improve access of local anesthetics to the nerve, thereby improving nerve block performance. We assessed the effects of six CPEs on nerve blockade from tetrodotoxin (TTX) and from bupivacaine. Each of the six surfactants, representing three CPE subgroups (anionic, cationic, and nonionic surfactants) was coinjected with TTX or bupivacaine at the sciatic nerve of Sprague-Dawley rats. Myotoxicity of CPEs, alone and with TTX, was assessed in vitro in C2C12 myotubes and in vivo via histological analysis. All enhancers produced marked concentration-dependent improvements in the frequency and duration of block with TTX but not bupivacaine. An in vitro toxicity assay showed a wide range of CPE myotoxicity, but in vivo histological assessment showed no signs of muscle or nerve damage at concentrations of CPEs that produced a half-maximal increase in the duration of block of TTX (except in the case of the cationic surfactant DDAB). This study demonstrates that CPEs can provide marked prolongation of nerve blockade from TTX but not bupivacaine, without apparent local tissue toxicity. These results may enhance the clinical applicability of TTX for prolonged-duration local anesthesia.
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Affiliation(s)
- Emmanuel J Simons
- Harvard-MIT Division of Health Sciences and Technology, Harvard Medical School, Boston, Massachusetts, USA
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Affiliation(s)
- Charles Berde
- Division of Pain Medicine, Department of Anesthesiology, Perioperative and Pain Medicine, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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