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Sinha S, Thapa S, Singh S, Dutt R, Verma R, Pandey P, Mittal V, Rahman MH, Kaushik D. Development of biocompatible nanoparticles of tizanidine hydrochloride in orodispersible films: In vitro characterization, ex vivo permeation and cytotoxic study on carcinoma cells. Curr Drug Deliv 2022; 19:1061-1072. [PMID: 35319369 DOI: 10.2174/1567201819666220321111338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 12/06/2021] [Accepted: 01/05/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND The main limitations of the therapeutic effectiveness of tizanidine hydrochloride (TNZ) are its low bioavailability due to its tendency to undergo first-pass metabolism and short biological half-life. These factors make it an ideal candidate for formulating orally disintegrating films. METHODS The fast-dissolving film of TNZ HCl was prepared by the solvent-casting method and characterized using scanning electron microscopy, FTIR and XRD, and evaluated for critical quality attributes for this type of dosage forms such as disintegration time, tensile strength, drug content, dissolution, and ex-vivo permeability. In vitro cytotoxicity studies were also conducted on cancer cell lines to confirm cytotoxic effect. OBJECTIVE The present study was aimed to prepare nanoparticles of tizanidine hydrochloride using biodegradable polymers and loading them on orodispersible films to obtain a sustained release dissolution profile with improved permeability and further study the cytotoxicity on A549 lung carcinoma cells, MCF7 breast cancer cells and HOP 92 non-small lung adenocarcinoma cells. RESULTS The polymeric matrix containing the drug provided a rapid disintegration time varying between 7±2 and 30±2 seconds, adequate tensile strength between 1.4 and 11.25 N/mm2, and improved permeability through porcine buccal mucosa when compared to the reference product. CONCLUSION A study of cytotoxic effect on the MCF-7 breast cancer cells and A549 lung carcinoma cells revealed that tizanidine hydrochloride nanoparticles at 2.3 mg/film exhibited an IC50 value of 65.1 % cytotoxicity on MCF-7, approximately 100% on HOP92, and 83.5 % on A549 lung carcinoma cells, thus paving the way for a new paradigm of research for cytotoxic study on MCF-7, HOP92 and A549 cell lines using the subject drug model prepared as oral films or biodegradable nanoparticles in oral films for site-specific targeting.
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Affiliation(s)
- Suhani Sinha
- Department of Pharmacy, School of Medical and Allied Sciences, G.D. Goenka University, Gurugram-122103, India
| | - Sonia Thapa
- Academy of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Cancer Pharmacology Division, Jammu-180001, India
| | - Shashank Singh
- Academy of Scientific and Innovative Research, CSIR-Indian Institute of Integrative Medicine, Cancer Pharmacology Division, Jammu-180001, India
| | - Rohit Dutt
- Department of Pharmacy, School of Medical and Allied Sciences, G.D. Goenka University, Gurugram-122103, India
| | - Ravinder Verma
- Department of Pharmacy, School of Medical and Allied Sciences, G.D. Goenka University, Gurugram-122103, India
| | - Parijat Pandey
- Department of Pharmaceutical Sciences, Gurugram University, Gurugram - 122413, India
| | - Vineet Mittal
- Department of Pharmaceutical Sciences, M.D. University, Rohtak (124001), Haryana, India
| | - Md Habibur Rahman
- Department of Pharmacy, Southeast University, Banani, Dhaka-1213, Bangladesh
| | - Deepak Kaushik
- Department of Pharmaceutical Sciences, M.D. University, Rohtak (124001), Haryana, India
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Vila J, Morgenstern A, Vendrell L, Ortega J, Danés I. Liver, Renal, and Cardiovascular Failure After Unintentional Overdose of Tizanidine in a 2-Year-Old Child. J Pediatr Pharmacol Ther 2021; 26:643-646. [PMID: 34421416 DOI: 10.5863/1551-6776-26.6.643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 01/08/2021] [Indexed: 11/11/2022]
Abstract
Tizanidine is a central alpha-2 adrenergic receptor agonist indicated for the treatment of spasticity in adults; however, its use in the pediatric population is considered off-label. In adults, the dose is gradually titrated until the desired reduction in muscle tone is achieved. Hypotension is a frequent adverse effect, but impaired liver function is not characteristic of alpha-2 adrenergic agonist overdose. We report a 2-year-old male affected with spastic quadriplegia (treated with clonazepam and tizanidine) and dysphagia (he was fed by nasogastric tube). Two days before admission caregivers ran out of clonazepam so they increased the tizanidine dose from 0.15 mg/kg/day to 1.6 mg/kg/day. Simultaneously his nasogastric tube fell out; therefore, he was unable to maintain proper oral nutrition and hydration. He presented to the emergency department hemodynamically unstable, with impaired consciousness and signs of severe dehydration. Blood tests revealed hepatic dysfunction without cholestasis and renal dysfunction. He was transferred to the pediatric intensive care unit. Treatment was mainly supportive, apart from tizanidine discontinuation. Metabolic and infectious diseases were ruled out so he was finally diagnosed as having liver, renal, and cardiovascular failure after tizanidine overdose, worsened by dehydration. His clinical status improved, and after 3 weeks he was discharged from the hospital, receiving clonidine instead of tizanidine to treat spasticity. Tizanidine overdose can result in serious complications that can be worsened because of patient comorbidities.
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Deputy SR, Tilton AH. Treatment of Disorders of Tone and Other Considerations in Pediatric Movement Disorders. Neurotherapeutics 2020; 17:1713-1723. [PMID: 33410106 PMCID: PMC7851300 DOI: 10.1007/s13311-020-00984-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2020] [Indexed: 12/26/2022] Open
Abstract
Pediatric movement disorders (PMDs) consist of a heterogeneous group of signs and symptoms caused by numerous neurological diseases. Different neurological disorders in children also share overlapping movement disorders making a diagnosis of the underlying cause of the movement disorder challenging. The similarity of the symptoms across multiple disease types suggests that there may be a final common motor pathway causing the overlapping movement disorders. There are numerous disorders in children associated with disturbances in tone and involuntary movements. This chapter will focus primarily on those disorders that involve abnormalities of tone and other important considerations of pediatric movement disorders. This chapter will address rating scales and goals for treatment and will include a review of symptomatic treatment and, where possible, the treatment of the underlying disease processes. The chapter will review representative disorders, including an inborn error of metabolism, an autoimmune disorder, and a group of neurodegenerative disorders. These examples demonstrate how the disorder's underlying pathophysiology results in a specific approach to the underlying disease and the associated conditions of tone and involuntary movements. Finally, the multiple treatment options for cerebral palsy and considerations of cerebral palsy mimics will be discussed.
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Affiliation(s)
- Stephen R Deputy
- Department of Neurology, Division of Child Neurology, Louisiana State University Health Sciences Center at New Orleans, Children's Hospital, 200 Henry Clay Ave., New Orleans, LA, 70118, USA
| | - Ann H Tilton
- Department of Neurology, Division of Child Neurology, Louisiana State University Health Sciences Center at New Orleans, Children's Hospital, 200 Henry Clay Ave., New Orleans, LA, 70118, USA.
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Gobetti C, Balsan ME, Ayres MV, de Almeida SHO, de Saldanha Simon E, Wingert NR, Oppe TP, Garcia CV. Development and Stability Control of Pediatric Oral Tizanidine Hydrochloride Formulations for Hospital Use. AAPS PharmSciTech 2020; 21:210. [PMID: 32729029 DOI: 10.1208/s12249-020-01751-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/07/2020] [Indexed: 11/30/2022] Open
Abstract
Tizanidine hydrochloride is a centrally acting skeletal muscle relaxant used in the treatment of spasticity. This drug is sold only as tablets or capsules, which highlights the need to develop oral liquid formulations that allow administration to children and adults with impaired swallowing. This study aim was to develop and improve tizanidine hydrochloride liquid formulations from raw material and to evaluate their stability. A stability-indicating high performance liquid chromatography method was validated for two formulations developed. Fifteen formulations were developed containing syrup and fifteen containing sodium carboxymethyl cellulose as vehicles, to select the two most suitable for stability testing. The formulations were prepared in triplicate and placed in amber polyethylene terephthalate and glass bottles, which were stored under three different conditions: at room temperature (15-30°C), under refrigeration (2-8°C), and at 40°C. The physicochemical and microbiological stability of formulations were evaluated, applying high performance liquid chromatography and microbiological count. The studied formulations at 15-30°C, 2-8°C, and 40°C can be used for a period of 70 days, and all parameters are inside of recommended specifications, enough to allow its use in the context for which it was developed, the application in hospital. The formulations developed in this work have simple components to avoid adverse reactions in vulnerable populations. Results of this study could be applied as a reference for hospital use; once it demonstrated the reliability of storage time interval and proper conditions for use.
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Pimenov OY, Galimova MH, Evdokimovskii EV, Averin AS, Nakipova OV, Reyes S, Alekseev AE. Myocardial α2-Adrenoceptors as Therapeutic Targets to Prevent Cardiac Hypertrophy and Heart Failure. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s000635091905021x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
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Xing XW, Sun YF, Zhao J, Pan ZX, Jiang WX. Tizanidine hydrochloride exhibits a cytotoxic effect on osteosarcoma cells through the PI3K/AKT signaling pathway. J Int Med Res 2019; 47:3792-3802. [PMID: 31179788 PMCID: PMC6726809 DOI: 10.1177/0300060519850395] [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] [Indexed: 01/12/2023] Open
Abstract
Objectives α2-adrenergic receptors are reportedly involved in cancer cell proliferation, invasion, and apoptosis through regulation of diverse molecules, which implies that it contributes to tumor progression. However, the functional significance of α2-adrenergic receptors in osteosarcoma (OS) is unclear. Tizanidine hydrochloride (THC), an α2-adrenergic receptor agonist, is often used to alleviate symptoms of spasticity. This study investigated the functional implications of THC treatment on human OS cells and the underlying mechanisms of resulting changes. Methods The proliferation of U2 OS cells was assessed by Cell Counting Kit-8; the migration and invasion capacities of U2 OS cells were then analyzed by transwell assay. Moreover, apoptosis in U2 OS cells was evaluated by flow cytometry and western blot analyses. Additionally, expression levels of key proteins in the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signaling pathway were measured. Results THC inhibited the proliferation, migration, and invasion of U2 OS cells, but promoted apoptosis within these cells. Expression levels of p-AKT, p-mTOR, and p-P70S6K were reduced by exposure to THC, suggesting involvement of PI3K/AKT signaling in THC-induced cytotoxicity within OS cells. Conclusions THC may play a novel role in OS cell cytotoxicity, and these findings suggest a potent therapeutic strategy for OS treatment.
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Affiliation(s)
- Xue-Wu Xing
- 1 Department of Orthopedics, Tianjin First Central Hospital, Tianjin, P.R. China
| | - Yu-Fu Sun
- 1 Department of Orthopedics, Tianjin First Central Hospital, Tianjin, P.R. China
| | - Jun Zhao
- 2 Department of Bone and Soft Tissue Tumor, Tianjin Medical University Cancer Institute & Hospital, Tianjin, P.R. China
| | - Zi-Xiang Pan
- 1 Department of Orthopedics, Tianjin First Central Hospital, Tianjin, P.R. China
| | - Wen-Xue Jiang
- 1 Department of Orthopedics, Tianjin First Central Hospital, Tianjin, P.R. China
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Alekseev AE, Park S, Pimenov OY, Reyes S, Terzic A. Sarcolemmal α2-adrenoceptors in feedback control of myocardial response to sympathetic challenge. Pharmacol Ther 2019; 197:179-190. [PMID: 30703415 DOI: 10.1016/j.pharmthera.2019.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
α2-adrenoceptor (α2-AR) isoforms, abundant in sympathetic synapses and noradrenergic neurons of the central nervous system, are integral in the presynaptic feed-back loop mechanism that moderates norepinephrine surges. We recently identified that postsynaptic α2-ARs, found in the myocellular sarcolemma, also contribute to a muscle-delimited feedback control capable of attenuating mobilization of intracellular Ca2+ and myocardial contractility. This previously unrecognized α2-AR-dependent rheostat is able to counteract competing adrenergic receptor actions in cardiac muscle. Specifically, in ventricular myocytes, nitric oxide (NO) and cGMP are the intracellular messengers of α2-AR signal transduction pathways that gauge the kinase-phosphatase balance and manage cellular Ca2+ handling preventing catecholamine-induced Ca2+ overload. Moreover, α2-AR signaling counterbalances phospholipase C - PKC-dependent mechanisms underscoring a broader cardioprotective potential under sympathoadrenergic and angiotensinergic challenge. Recruitment of such tissue-specific features of α2-AR under sustained sympathoadrenergic drive may, in principle, be harnessed to mitigate or prevent cardiac malfunction. However, cardiovascular disease may compromise peripheral α2-AR signaling limiting pharmacological targeting of these receptors. Prospective cardiac-specific gene or cell-based therapeutic approaches aimed at repairing or improving stress-protective α2-AR signaling may offer an alternative towards enhanced preservation of cardiac muscle structure and function.
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Affiliation(s)
- Alexey E Alekseev
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA; Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, Pushchino, Moscow Region 142290, Russia.
| | - Sungjo Park
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
| | - Oleg Yu Pimenov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, Pushchino, Moscow Region 142290, Russia
| | - Santiago Reyes
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
| | - Andre Terzic
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA
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Pei W, Zou Y, Wang W, Wei L, Zhao Y, Li L. Tizanidine exerts anti-nociceptive effects in spared nerve injury model of neuropathic pain through inhibition of TLR4/NF-κB pathway. Int J Mol Med 2018; 42:3209-3219. [PMID: 30221670 PMCID: PMC6202089 DOI: 10.3892/ijmm.2018.3878] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 02/12/2018] [Indexed: 01/26/2023] Open
Abstract
Recently, α2-adrenoceptors (α2-AR) agonists have been shown to have anti-nociceptive effects and thus may become a promising therapeutic strategy for neuropathic pain. tizanidine is a highly selective α2-AR agonist, but the effect mechanism of tizanidine in neuropathic pain remains largely unknown. The present study investigated whether tizanidine has anti-nociceptive effects in spared nerve injury (SNI) model of neuropathic pain in rats, as well as explored the underlying molecular mechanism. We found that the rats in SNI group showed significantly higher mechanical and thermal hyperalgesia, accompanied with increased production of proinflammatory cytokines including interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α), as well as the activation of Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling. PDTC, an inhibitor of TLR4/NF-κB signaling, could significantly attenuate the SNI-induced mechanical and thermal hyperalgesia and the production of proinflammatory cytokines. Moreover, treatment with tizanidine also attenuated the SNI-induced mechanical and thermal hyperalgesia, suppressed production of the proinflammatory cytokines, and inhibited the activation of TLR4/NF-κB pathway, which could be reversed by pretreatment with BRL44408, a selective α2-AR antagonist. Taken these findings together, we demonstrated that tizanidine has anti-nociceptive effects on neuropathic pain via inhibiting the production of proinflammatory cytokines through suppressing the activation of TLR4/NF-κB p65 signaling pathway.
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Affiliation(s)
- Wanmin Pei
- Department of Anesthesia, Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
| | - Yi Zou
- Department of Anesthesia, People's Hospital of Hunan Province, Changsha, Hunan 410005, P.R. China
| | - Wenting Wang
- Department of Anesthesia, People's Hospital of Hunan Province, Changsha, Hunan 410005, P.R. China
| | - Lai Wei
- Department of Anesthesia, People's Hospital of Hunan Province, Changsha, Hunan 410005, P.R. China
| | - Yuan Zhao
- Department of Anesthesia, People's Hospital of Hunan Province, Changsha, Hunan 410005, P.R. China
| | - Li Li
- Department of Anesthesia, Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China
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Talakoub R, Abbasi S, Maghami E, Zavareh SMHT. The effect of oral tizanidine on postoperative pain relief after elective laparoscopic cholecystectomy. Adv Biomed Res 2016; 5:19. [PMID: 26962521 PMCID: PMC4770607 DOI: 10.4103/2277-9175.175905] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 09/14/2015] [Indexed: 11/29/2022] Open
Abstract
Background: Cholecystectomy is considered as the most important and relatively common postoperative pain control often begins in recovery room by using systemic narcotics that may have some side effects. The aim of this study is to evaluate the effect of premedication with oral tizanidine on pain relief after elective laparoscopic cholecystectomy. Materials and Methods: In this double-blinded clinical trial, 70 adults of American Society of Anesthesiologist physiologic state 1 and 2 scheduled for elective laparoscopic cholecystectomy under general anesthesia were studied and randomly divided in two study and control groups. Ninety minutes before the induction of anesthesia, patients received either 4 mg tizanidine (study group) orally in 50cc or the same volume of plain water as a placebo (control group). Then, the vital signs, pain intensity, duration of stay in recovery, and the analgesic consumption were measured and then compared in both groups during 24 h postoperatively. Results: There was no significant difference in patient characteristics, with respect to age, weight, gender, and duration of anesthesia and surgery between the groups (P > 0.05). The pain intensity, need for analgesic drugs (34.57 ± 8.88 mg vs. 101.86 ± 5.08 mg), and the duration of stay in recovery room (67.43 ± 1.59 min vs. 79.57 ± 5.48 min) were significantly lower in tizanidine group than that of the control group. Conclusion: Oral administration of 4 mg tizanidine before laparoscopic cholecystectomy reduces postoperative pain, opioid consumption, and consequence of the duration of stay in recovery room without any complication.
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Affiliation(s)
- Reihanak Talakoub
- Department of Anesthesiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Saeed Abbasi
- Department of Anesthesiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Elham Maghami
- Department of Anesthesiology, Isfahan University of Medical Sciences, Isfahan, Iran
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Tabari M, Alipour M, Esalati H. Evaluation of Oral Tiazinidine Effects on [intraoperative] Hemodynamic Responses During Direct Laryngoscopy Under General Anesthesia. IRANIAN RED CRESCENT MEDICAL JOURNAL 2013; 15:541-6. [PMID: 24396571 PMCID: PMC3871739 DOI: 10.5812/ircmj.11540] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/23/2013] [Accepted: 05/31/2013] [Indexed: 11/30/2022]
Abstract
Background Direct laryngoscopy and tracheal intubation can result in blood pressure and heart rate increase which in turn may lead to myocardial ischemia, cerebral hemorrhage, and even death in susceptible patients. Tizanidine is α2-receptor agonists that suppresses central sympathetic system. Objectives This study evaluates the effects of oral Tizanidine on hemodynamic responses during operations and aims to determine the appropriate Propofol dosage to maintain anesthesia under BIS monitoring. Materials and Methods A double-blind clinical trial has been performed on 70 candidates for elective abdominal surgery undergoing general anesthesia in Educational Hospital of Ghaem, Mashhad, Iran. 35 randomly selected patients (the case group) were given 4 mg of oral Tizanidine 90 minutes before the induction of anesthesia whereas the remaining subjects (the control group) were given placebo. Blood pressure and heart rate before and after induction of anesthesia, and after intubation and extubation, existence of postoperative shivering, and the needed Propofol dosage were measured and recorded. Data analysis was done with T-test and Chi-squared test, using SPSS software version 16. Results Variations of blood pressure and heart rate after anesthesia induction, intubation and extubation were less in Tizanidine group generally. Postoperative shivering was reported in 28.6% and 11.4% of patients in control and case group respectively. Average propofol needed dose for anesthesia maintenance in case group was 25% less than the needed amount in the control group. Conclusions Using oral Tizanidine as a premedication, yielded stability in blood pressure and heart rate during surgery and decreased required Propofol. Considering its short duration of action, Tizanidine use as a premedication is recommended for sedation and stabilization of hemodynamic responses during the operations.
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Affiliation(s)
- Masoomeh Tabari
- Department of Anesthesiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
- Corresponding author: Masoomeh Tabari, Department of Anesthesiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran, Tel/Fax: +98-5118424685, E-mail:
| | - Mohammad Alipour
- Department of Anesthesiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Hamideh Esalati
- Department of Anesthesiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
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Abstract
Pediatric onset multiple sclerosis (MS) may be seen in 2-5% of patients with MS. It is characterized by high disease burden. As such, early treatment with preventative therapies should be considered. Although randomized controlled trials have not been conducted on therapies for pediatric MS, there is a growing body of literature suggesting safety of first-line agents approved for use in adult MS, including interferons and glatiramer acetate. The use of second-line therapies, such as natalizumab, cyclophosphamide, and mitoxantrone has been described in a small number of pediatric MS cases. These case series suggest benefit of these agents after limited follow-up. Little information on long-term effects of therapies such as cyclophosphamide, mitoxantrone, or natalizumab is available for this population, although concerns of increased risk for opportunistic infections (progressive multifocal leukoencephalopathy with natalizumab) and secondary hematologic cancers (with mitoxantrone) exist. Finally, although fatigue, motor, cognitive, and psychosocial difficulties are common in this population, no trials have been conducted on pharmacologic or non-pharmacologic interventions for the management of these problems. Therapies for spasticity, including baclofen (including the baclofen pump), diazepam, and botulinum toxin have been evaluated in children with cerebral palsy and may be used safely in children. Psychiatric intervention is often necessary for affective disorders. Interventions for fatigue have not been studied, although evidence in the adult MS literature suggests possible benefit of exercise and modafinil. This article provides a practical guide to the diagnosis and treatment of multiple sclerosis in pediatric patients.
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Affiliation(s)
- E Ann Yeh
- Department of Pediatrics (Neurology), University of Toronto, ON, Canada.
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Doxazosin Versus Tizanidine for Treatment of Dysfunctional Voiding in Children: A Prospective Randomized Open-labeled Trial. Urology 2012; 79:428-33. [DOI: 10.1016/j.urology.2011.10.043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 10/14/2011] [Accepted: 10/21/2011] [Indexed: 11/20/2022]
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Kaddar N, Vigneault P, Pilote S, Patoine D, Simard C, Drolet B. Tizanidine (Zanaflex): a muscle relaxant that may prolong the QT interval by blocking IKr. J Cardiovasc Pharmacol Ther 2011; 17:102-9. [PMID: 21317414 DOI: 10.1177/1074248410395020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Tizanidine (Zanaflex) is a centrally acting imidazoline muscle relaxant that is structurally similar to clonidine (α(2)-adrenergic agonist) but not to other myorelaxants such as baclofen or benzodiazepines. Interestingly, cardiac arrhythmias and QT interval prolongation have been reported with tizanidine. OBJECTIVE To evaluate the effects of tizanidine on cardiac ventricular repolarization. METHODS (1) Whole-cell patch-clamp experiments: HERG- or KCNQ1+KCNE1-transfected cells were exposed to tizanidine 0.1-100 µmol/L (n = 29 cells, total) to assess drug effect on the rapid (I(Kr)) and slow (I(Ks)) components of the delayed rectifier potassium current. (2) Langendorff retroperfusion experiments: isolated hearts from male Hartley guinea pigs (n = 6) were exposed to tizanidine 1 µmol/L to assess drug-induced prolongation of monophasic action potential duration measured at 90% repolarization (MAPD(90)). (3) In vivo wireless cardiac telemetry experiments: guinea pigs (n = 6) implanted with radio transmitters were injected a single intraperitoneal (ip) dose of tizanidine 0.25 mg/kg and 24 hours electrocardiography (ECG) recordings were made. RESULTS (1) Patch-clamp experiments revealed an estimated IC(50) for tizanidine on I(Kr) above 100 µmol/L. Moreover, tizanidine 1 µmol/L had hardly any effect on I(Ks) (5.23% ± 4.54% inhibition, n = 5 cells). (2) While pacing the hearts at stimulation cycle lengths of 200 or 250 ms, tizanidine 1 µmol/L prolonged MAPD(90) by 8.22 ± 2.03 (6.7%) and 11.70 ± 3.08 ms (8.5%), respectively (both P < .05 vs baseline). (3) Tizanidine 0.25 mg/kg ip caused a maximal 11.93 ± 1.49 ms prolongation of corrected QT interval (QTc), 90 minutes after injection. CONCLUSION Tizanidine prolongs the QT interval by blocking I(Kr). Patients could be at risk of cardiac proarrhythmia during impaired drug elimination, such as in case of CYP1A2 inhibition during drug interactions.
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Affiliation(s)
- Nisrin Kaddar
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Québec, QC Canada
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