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Oggianu L, Garrone B, Fiorentini F, Del Bene F, Rosignoli MT, Di Giorgio FP, Kaminski RM. PK/PD analysis of trazodone and gabapentin in neuropathic pain rodent models: Translational PK-PD modeling from nonclinical to clinical development. Clin Transl Sci 2023; 16:606-617. [PMID: 36785922 PMCID: PMC10087074 DOI: 10.1111/cts.13472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/23/2022] [Accepted: 12/17/2022] [Indexed: 02/15/2023] Open
Abstract
A pharmacokinetic/pharmacodynamic (PK/PD) model was developed to describe the time course of writhings after intraperitoneal injection of acetic acid in mice. The model was applied to investigate the antinociceptive effect of trazodone and gabapentin alone and in combination. Writhings time course was described by a transit compartment model with the delay due to the transit of the acetic acid being represented by a chain of intermediate compartments. In the drug-treated animals, the number of writhings decreases according to a k2 factor linking drug concentration and antinociceptive effect. Compounds' potency parameters were 10.9 and 0.0459 L/μmoles/min for trazodone and gabapentin, respectively, indicating a much higher in vivo potency of trazodone in the PD writhing test. The PK/PD parameters were used to simulate the expected writhing counts in mice at combined doses without efficacy alone, assuming pharmacological additivity. Simulation results indicated that, at low dose combinations, experimental data were mostly below the simulated writhings median, suggesting possible synergic effect. Such hypothesis was tested by adding the γ parameter in the PK/PD model to represent the deviation from the assumption of no-interaction, leading to a reduction of the objective function compared to the additive model. On this basis, several simulations were performed to identify possible starting dose combinations of trazodone and gabapentin in humans, by selecting doses yielding systemic exposures close to those being synergic in the mouse. Simulations indicated that doses of 50-100 mg trazodone could enhance gabapentin antinociceptive effect in humans, supporting the development of a low dose combination for optimal analgesia treatment.
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Garrone B, di Matteo A, Amato A, Pistillo L, Durando L, Milanese C, Di Giorgio FP, Tongiani S. Synergistic interaction between trazodone and gabapentin in rodent models of neuropathic pain. PLoS One 2021; 16:e0244649. [PMID: 33395416 PMCID: PMC7781482 DOI: 10.1371/journal.pone.0244649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/14/2020] [Indexed: 01/17/2023] Open
Abstract
Neuropathic pain is a chronic debilitating condition caused by injury or disease of the nerves of the somatosensory system. Although several therapeutic approaches are recommended, none has emerged as an optimal treatment leaving a need for developing more effective therapies. Given the small number of approved drugs and their limited clinical efficacy, combining drugs with different mechanisms of action is frequently used to yield greater efficacy. We demonstrate that the combination of trazodone, a multifunctional drug for the treatment of major depressive disorders, and gabapentin, a GABA analogue approved for neuropathic pain relief, results in a synergistic antinociceptive effect in the mice writhing test. To explore the potential relevance of this finding in chronic neuropathic pain, pharmacodynamic interactions between low doses of trazodone (0.3 mg/kg) and gabapentin (3 mg/kg) were evaluated in the chronic constriction injury (CCI) rat model, measuring the effects of the two drugs both on evoked and spontaneous nociception and on general well being components. Two innate behaviors, burrowing and nest building, were used to assess these aspects. Besides exerting a significant antinociceptive effect on hyperalgesia and on spontaneous pain, combined inactive doses of trazodone and gabapentin restored in CCI rats innate behaviors that are strongly reduced or even abolished during persistent nociception, suggesting that the combination may have an impact also on pain components different from somatosensory perception. Our results support the development of a trazodone and gabapentin low doses combination product for optimal multimodal analgesia treatment.
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Monteiro BP, de Lorimier LP, Moreau M, Beauchamp G, Blair J, Lussier B, Pelletier JP, Troncy E. Pain characterization and response to palliative care in dogs with naturally-occurring appendicular osteosarcoma: An open label clinical trial. PLoS One 2018; 13:e0207200. [PMID: 30521538 PMCID: PMC6283659 DOI: 10.1371/journal.pone.0207200] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 10/26/2018] [Indexed: 12/22/2022] Open
Abstract
This study aimed to characterize bone cancer pain (quantitative sensory testing (QST), stance asymmetry index, actimetry, scores of pain and quality of life (QoL)) in dogs with appendicular osteosarcoma (OSA), and to evaluate a stepwise palliative analgesic treatment. The pain profile of thirteen client-owned dogs with OSA was compared with seven healthy dogs. Dogs with OSA were then enrolled in a prospective, open-label, clinical trial. Outcome measures included: primary and secondary mechanical thresholds (MT), conditioned pain modulation (CPM), stance asymmetry index, actimetry (most and least active periods), visual analog scales and QoL. After baseline assessments, stepwise treatment comprised orally administered cimicoxib (2 mg/kg q 24h), amitriptyline (1–1.5 mg/kg q 24h) and gabapentin (10 mg/kg q 8h); re-evaluations were performed after 14 (D14), 21 (D21) and 28 (D28) days, respectively. Statistics used mixed linear models (α = 5%; one-sided). Centralized nociceptive sensitivity (primary and secondary MT, and dynamic allodynia) was recorded in OSA dogs. Healthy dogs had responsive CPM, but CPM was deficient in OSA dogs. Construct validity was observed for the QST protocol. Asymmetry index was significantly present in OSA dogs. The CPM improved significantly at D14. When compared with baseline (log mean ± SD: 4.1 ± 0.04), most active actimetry significantly improved at D14 (4.3 ± 0.04), D21 and D28 (4.2 ± 0.04 for both). When compared with baseline, least active actimetry significantly decreased after treatment at all time-points indicating improvement in night-time restlessness. No other significant treatment effect was observed. Except for tactile threshold and actimetry, all outcomes worsened when gabapentin was added to cimicoxib-amitriptyline. Dogs with bone cancer are affected by widespread somatosensory sensitivity characterized by peripheral and central sensitization and have a deficient inhibitory system. This severe pain is mostly refractory to palliative analgesic treatment, and the latter was only detected by specific and sensitive outcomes.
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Affiliation(s)
- Beatriz P. Monteiro
- GREPAQ (Groupe de recherche en pharmacologie animale du Québec), Department of biomedical sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | | | - Maxim Moreau
- GREPAQ (Groupe de recherche en pharmacologie animale du Québec), Department of biomedical sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Guy Beauchamp
- GREPAQ (Groupe de recherche en pharmacologie animale du Québec), Department of biomedical sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | - Jeffrey Blair
- Vétoquinol SA, Global–Le Groupe Vétoquinol, Magny-Vernois, France
| | - Bertrand Lussier
- GREPAQ (Groupe de recherche en pharmacologie animale du Québec), Department of biomedical sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Jean-Pierre Pelletier
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
| | - Eric Troncy
- GREPAQ (Groupe de recherche en pharmacologie animale du Québec), Department of biomedical sciences, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Osteoarthritis Research Unit, University of Montreal Hospital Research Centre (CRCHUM), Montreal, Quebec, Canada
- * E-mail:
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Akbari E, Mirzaei E, Rezaee L, Zarrabian S, Haghparast A. The effect of amitriptyline administration on pain-related behaviors in morphine-dependent rats: Hypoalgesia or hyperalgesia? Neurosci Lett 2018; 683:185-189. [PMID: 30081059 DOI: 10.1016/j.neulet.2018.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 07/31/2018] [Accepted: 08/02/2018] [Indexed: 11/25/2022]
Abstract
Pain control in opioid-dependent individuals is a clinical complication. The present study investigated the effects of different doses of amitriptyline in the three stages of the formalin test in morphine-dependent rats (MDRs). Morphine dependency was induced using the oral method, and then, amitriptyline-induced antinociceptive effects were measured at 4 doses (2.5, 5, 10, and 20 mg/kg) and compared with the control group in a formalin-based model of pain. There was no observed antinociceptive effect in the MDRs and morphine-naïve rats (MNRs) in phase I. In the interphase, amitriptyline induced pain suppression at doses of 5 and 20 mg/kg. In phase II, at doses of 5, 10, and 20 mg/kg, the hypoalgesic effect on pain-related behaviors was seen in the MNRs. In MDRs, amitriptyline at doses of 2.5 and 5 mg/kg caused the hyperalgesic effect, whereas at 10 and 20 mg/kg doses, it induced a hypoalgesic effect. A significant attenuation was observed in the latency to fall from the accelerating rotarod at doses of 10 and 20 mg/kg in the MDRs, and at a dose of 20 mg/kg in the MNRs. Data showed that amitriptyline dose-dependently induced paradoxical hypo- and hyper-algesic effects in MDRs.
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Affiliation(s)
- Esmaeil Akbari
- Immunogenetic Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran; Department of Physiology and Pharmacology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ebrahim Mirzaei
- School of Pharmacy, Mazandaran University of Medical Sciences, Sari, Iran
| | - Laleh Rezaee
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahram Zarrabian
- Cognitive and Neuroscience Research Center (CNRC), Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Godínez-Chaparro B, Quiñonez-Bastidas GN, Rojas-Hernández IR, Austrich-Olivares AM, Mata-Bermudez A. Synergistic Interaction of a Gabapentin- Mangiferin Combination in Formalin-Induced Secondary Mechanical Allodynia and Hyperalgesia in Rats Is Mediated by Activation of NO-Cyclic GMP-ATP-Sensitive K + Channel Pathway. Drug Dev Res 2017; 78:390-402. [PMID: 28940250 DOI: 10.1002/ddr.21411] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/01/2017] [Indexed: 11/07/2022]
Abstract
Preclinical Research Gabapentin is an anticonvulsant used to treat neuropathic pain. Mangiferin is an antioxidant that has antinociceptive and antiallodynic effects in inflammatory and neuropathic pain models. The purpose of this study was to determine the interaction between mangiferin and gabapentin in the development and maintenance of formalin-induced secondary allodynia and hyperalgesia in rats. Gabapentin, mangiferin, or their fixed-dose ratio combination were administrated peripherally. Isobolographic analyses was used to define the nature of the interaction of antiallodynic and/or antihyperalgesic effects of the two compounds. Theoretical ED50 values for the combination were 74.31 µg/paw and 95.20 µg/paw for pre- and post-treatment, respectively. These values were higher than the experimental ED50 values, 29.45 µg/paw and 37.73 µg/paw respectively, indicating a synergistic interaction in formalin-induced secondary allodynia and hyperalgesia. The antiallodynic and antihyperalgesic effect induced by the gabapentin/mangiferin combination was blocked by administration of L-NAME, the soluble guanylyl cyclase inhibitor, ODQ and glibenclamide. These data suggest that the gabapentin- mangiferin combination produces a synergistic interaction at the peripheral level. Moreover, the antiallodynic and hyperalgesic effect induced by the combination is mediated via the activation of an NO-cyclic GMP-ATP-sensitive K+ channel pathway. Drug Dev Res 78 : 390-402, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Beatriz Godínez-Chaparro
- Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F, 04960, Mexico
| | - Geovanna Nallely Quiñonez-Bastidas
- Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F, 04960, Mexico
| | - Isabel Rocío Rojas-Hernández
- Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F, 04960, Mexico
| | - Amaya Montserrat Austrich-Olivares
- Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F, 04960, Mexico
| | - Alfonso Mata-Bermudez
- Departamento de Sistemas Biológicos, División de Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F, 04960, Mexico
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Formalin injection produces long-lasting hypersensitivity with characteristics of neuropathic pain. Eur J Pharmacol 2017; 797:83-93. [PMID: 28095324 DOI: 10.1016/j.ejphar.2017.01.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 01/11/2017] [Accepted: 01/13/2017] [Indexed: 01/12/2023]
Abstract
The purpose of this study was to investigate whether 1%, 2% or 5% formalin injection produce hypersensitivity with characteristics of the neuropathic pain induced by spinal nerve injury. Formalin injection (1%, 2% and 5%) produced concentration-dependent long-lasting (at least 14 days) mechanical allodynia and hyperalgesia in both paws. Likewise, L5/L6 spinal nerve ligation induced allodynia and hyperalgesia in both paws. The intensity of hypersensitivity was greater in the ipsilateral than in the contralateral paw in all models. Systemic gabapentin or morphine completely reduced 1% formalin-induced hypersensitivity. In contrast, both drugs were not able to fully diminish 2-5% formalin- and nerve injury-induced hypersensitivity. Indomethacin produced a significant effect in the chronic 1% formalin test. Conversely, this drug did not modify 2 or 5% formalin- and nerve injury-induced hypersensitivity. Spinal nerve injury and 2-5%, but not 1%, formalin injection enhanced ATF3 protein expression and immunofluorescence in dorsal root ganglia (DRG) in a time-dependent manner. Furthermore, 2-5%, but not 1%, formalin injection or spinal nerve injury also enhanced α2δ-1 subunit protein levels in DRG. Our results suggest that 5% and, at lesser extent, 2% formalin injection produces long-lasting hypersensitivity with a pharmacological and molecular pattern that resembles neuropathic pain induced by spinal nerve ligation.
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Zúñiga-Romero A, Ponce-Chávez MK, Gauthereau-Torres MY, Ortega-Varela LF. Combination of diacerhein and antiepileptic drugs after local peripheral, and oral administration in the rat formalin test. Drug Dev Res 2014; 75:510-20. [PMID: 25418935 DOI: 10.1002/ddr.21232] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 10/06/2014] [Indexed: 11/07/2022]
Abstract
Preclinical Research The present study was designed to evaluate the possible antinociceptive interaction between diacerhein and some antiepileptic drugs (carbamazepine, topiramate and gabapentin) on formalin-induced nociception. Diacerhein, each of the antiepileptics or a fixed dose-ratio combination of these drugs was assessed after local peripheral and oral administration in rats. lsobolographic analyses were used to define the interaction between drugs. Diacerhein, antiepileptic drugs (carbamazepine, topiramate and gabapentin) or their combinations yielded a dose-dependent antinociceptive effect when administered by both routes. Theoretical ED30 values for the combination estimated from the isobolograms were obtained as follows: diacerhein-carbamazepine (85.99 ± 7.07 μg/paw; 56.53 ± 4.56 mg/kg po), diacerhein-topiramate (197.97 ± 22.90 μg/paw; 13.06 ± 2.44 mg/kg po) and diacerhein-gabapentin (96.87 ± 17.73 μg/paw; 17.90 ± 4.70 mg/kg p.o.) for the local peripheral and oral administration routes, respectively. These values were significantly higher than the experimentally obtained ED30 values: diacerhein-carbamazepine (49.33 ± 3.37 μg/paw; 35.49 ± 7.91 mg/kg po), diacerhein-topiramate (133.00 ± 39.10 μg/paw; 8.87 ± 1.46 mg/kg po) and diacerhein-gabapentin (70.98 ± 14.73 μg/paw; 10.95 ± 3.23 mg/kg po). The combinations produced their antinociceptive effects without motor impairment in the rotarod test indicating synergistic interactions with a good side effect profile.
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Affiliation(s)
- Angel Zúñiga-Romero
- Facultad de Químico-Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, 58240, Morelia, Michoacán, México
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Hall FS, Schwarzbaum JM, Perona MTG, Templin JS, Caron MG, Lesch KP, Murphy DL, Uhl GR. A greater role for the norepinephrine transporter than the serotonin transporter in murine nociception. Neuroscience 2010; 175:315-27. [PMID: 21129446 DOI: 10.1016/j.neuroscience.2010.11.057] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 10/27/2010] [Accepted: 11/28/2010] [Indexed: 11/16/2022]
Abstract
Norepinephrine and serotonin involvement in nociceptive functions is supported by observations of analgesic effects of norepinephrine transporter (NET) and serotonin transporter (SERT) inhibitors such as amitriptyline. However, the relative contribution of NET and SERT to baseline nociception, as well as amitriptyline analgesia, is unclear. Amitriptyline and morphine analgesia in wild-type (WT) mice and littermates with gene knockout (KO) of SERT, NET or both transporters was conducted using the hotplate and tail-flick tests. Hypoalgesia was observed in NET KO mice, and to a lesser extent in SERT KO mice. The magnitude of this hypoalgesia in NET KO mice was so profound that it limited the assessment of drug-induced analgesia. Nonetheless, the necessary exclusion of these subjects because of profound baseline hypoalgesia strongly supports the role of norepinephrine and NET in basal nociceptive behavior while indicating a much smaller role for serotonin and SERT. To further clarify the role of NET and SERT in basal nociceptive sensitivity further experiments were conducted in SERT KO and NET KO mice across a range of temperatures. NET KO mice were again found to have pronounced thermal hypoalgesia compared to WT mice in both the hotplate and tail-flick tests, while only limited effects were observed in SERT KO mice. Furthermore, in the acetic acid writhing test of visceral nociception pronounced hypoalgesia was again found in NET KO mice, but no change in SERT KO mice. As some of these effects may have resulted from developmental consequences of NET KO, the effects of the selective NET blocker nisoxetine and the selective SERT blocker fluoxetine were also examined in WT mice: only nisoxetine produced analgesia in these mice. Collectively these data suggest that NET has a far greater role in determining baseline analgesia, and perhaps other analgesic effects, than SERT in mice.
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Affiliation(s)
- F S Hall
- National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD 21224, USA.
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Analysis of the antinociceptive interactions in two-drug combinations of gabapentin, oxcarbazepine and amitriptyline in streptozotocin-induced diabetic mice. Eur J Pharmacol 2010; 628:75-82. [DOI: 10.1016/j.ejphar.2009.11.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 10/26/2009] [Accepted: 11/10/2009] [Indexed: 11/20/2022]
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Gilron I, Bailey JM, Tu D, Holden RR, Jackson AC, Houlden RL. Nortriptyline and gabapentin, alone and in combination for neuropathic pain: a double-blind, randomised controlled crossover trial. Lancet 2009; 374:1252-61. [PMID: 19796802 DOI: 10.1016/s0140-6736(09)61081-3] [Citation(s) in RCA: 284] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Drugs for neuropathic pain have incomplete efficacy and dose-limiting side-effects when given as monotherapy. We assessed the efficacy and tolerability of combined nortriptyline and gabapentin compared with each drug given alone. METHODS In this double-blind, double-dummy, crossover trial, patients with diabetic polyneuropathy or postherpetic neuralgia, and who had a daily pain score of at least 4 (scale 0-10), were enrolled and treated at one study site in Canada between Nov 5, 2004, and Dec 13, 2007. 56 patients were randomised in a 1:1:1 ratio with a balanced Latin square design to receive one of three sequences of daily oral gabapentin, nortriptyline, and their combination. In sequence, a different drug was given to each randomised group in three treatment periods. During each 6-week treatment period, drug doses were titrated towards maximum tolerated dose. The primary outcome was mean daily pain at maximum tolerated dose. Analysis was by intention to treat. This trial is registered, number ISRCTN73178636. FINDINGS 45 patients completed all three treatment periods; 47 patients completed at least two treatment periods and were analysed for the primary outcome. Mean daily pain (0-10; numerical rating scale) was 5.4 (95% CI 5.0 to 5.8) at baseline, and at maximum tolerated dose, pain was 3.2 (2.5 to 3.8) for gabapentin, 2.9 (2.4 to 3.4) for nortriptyline, and 2.3 (1.8 to 2.8) for combination treatment. Pain with combination treatment was significantly lower than with gabapentin (-0.9, 95% CI -1.4 to -0.3, p=0.001) or nortriptyline alone (-0.6, 95% CI -1.1 to -0.1, p=0.02). At maximum tolerated dose, the most common adverse event was dry mouth, which was significantly less frequent in patients on gabapentin than on nortriptyline (p<0.0001) or combination treatment (p<0.0001). No serious adverse events were recorded for any patients during the trial. INTERPRETATION Combined gabapentin and nortriptyline seems to be more efficacious than either drug given alone for neuropathic pain, therefore we recommend use of this combination in patients who show a partial response to either drug given alone and seek additional pain relief. Future trials should compare other combinations to their respective monotherapies for treatment of such pain. FUNDING Canadian Institutes of Health Research.
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Affiliation(s)
- Ian Gilron
- Department of Anesthesiology, Queen's University, Kingston, ON, Canada.
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11
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Abstract
PURPOSE OF REVIEW With the aging of the population, treatment of painful neuropathies is becoming more and more important for neurological practice. This short review highlights recent findings and current problems. RECENT FINDINGS In addition to tricyclic antidepressants and gabapentin, the reliability of which is established, some drugs have more recently been demonstrated to be efficacious: major and minor opioids, pregabalin, and serotonin-noradrenaline-reuptake inhibitors. In contrast, some other drugs have yielded disappointing results: memantine, mexiletine, topiramate, and - very recently - lamotrigine. Three main questions are currently being debated. Notwithstanding their proven efficacy, should opioids be used in chronic noncancer pain? In which patients should serotonin-noradrenaline-reuptake inhibitors be preferred to tricyclic antidepressants? What is the difference between pregabalin and gabapentin? The whole field suffers from important limitations that make evidence-based medical data hard to translate in clinical practice: most clinical trials were and still are focused on two conditions only (diabetic neuropathy and postherpetic neuralgia) and studies on polytherapy are insufficient. SUMMARY A large variety of drugs are being tried in the treatment of painful neuropathy. Neurologists now have a wide choice. Recent publications can help in choosing the best treatment course.
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Affiliation(s)
- Giorgio Cruccu
- EFNS Panel Neuropathic Pain, Department of Neurological Sciences, La Sapienza University, Rome, Italy.
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Ortega-Varela LF, Herrera JE, Caram-Salas NL, Rocha-González HI, Granados-Soto V. Isobolographic analyses of the gabapentin-metamizol combination after local peripheral, intrathecal and oral administration in the rat. Pharmacology 2007; 79:214-22. [PMID: 17389816 DOI: 10.1159/000101390] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 12/22/2006] [Indexed: 02/02/2023]
Abstract
This study was designed to evaluate the possible antinociceptive interaction between gabapentin and metamizol on formalin-induced nociception. Gabapentin, metamizol or a fixed dose-ratio combination of both drugs were assessed after local peripheral, intrathecal and oral administration in rats. Isobolographic analyses were employed to define the nature of the interaction between drugs. Gabapentin, metamizol and gabapentin-metamizol combinations yielded a dose-dependent antinociceptive effect when administered by the three different routes. ED30 values were estimated for the individual drugs and isobolograms were constructed. Theoretical ED30 values for the combination estimated from the isobolograms were 21.11 +/- 1.17 microg/paw, 104.6 +/- 5.5 microg/rat and 78.8 +/- 5.5 mg/kg for the local peripheral, intrathecal and oral administration routes, respectively. These values were significantly higher than the experimentally obtained ED30 values which were 11.3 +/- 1.5 microg/paw, 36.8 +/- 3.1 microg/rat and 15 +/- 1.2 mg/kg indicating a synergistic interaction. Systemic administration resulted in the highest synergism. Data confirm that low doses of the gabapentin and metamizol can interact synergistically to reduce formalin-induced nociceptive behavior suggesting that this combination could be useful to treat inflammatory pain in humans.
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Affiliation(s)
- Luis F Ortega-Varela
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, México, DF, Mexico
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13
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Vissers KCP, Geenen F, Biermans R, Meert TF. Pharmacological correlation between the formalin test and the neuropathic pain behavior in different species with chronic constriction injury. Pharmacol Biochem Behav 2006; 84:479-86. [PMID: 16860855 DOI: 10.1016/j.pbb.2006.06.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2005] [Revised: 05/27/2006] [Accepted: 06/15/2006] [Indexed: 11/24/2022]
Abstract
Research on mechanisms of drug action, and preclinical screening of molecules with a potential activity on neuropathic pain requires extensive animal work. The chronic constriction injury model is one of the best-characterized models of neuropathic pain behavior in rats, but requires extensive time consuming operations and animal handling. The formalin test is easier to perform, and a well validated model. The latter may serve as an effective prescreening test of molecules and may facilitate drug targeting. In the present study the activity of different pharmacological reference compounds was tested in rats and gerbils on the cold plate for animals that had undergone chronic constriction injury and in the second phase of the formalin test. In rats, a comparable outcome in both test conditions was observed for morphine, fentanyl, MK-801 and flunarizine. Clonidine had more activity in the second phase of the formalin test, whereas baclofen, tramadol, amitryptiline, ketamine and topiramate showed more activity in the cold plate. In gerbils, both test conditions yielded comparable results for fentanyl and ketoprofen. Tramadol and CP-96345 tended to have more activity in the second phase of the formalin test, whereas morphine, SR-48968, SR-142801 and R116301 demonstrated more activity in the cold plate test. This study demonstrates a good correlation between the second phase of the formalin test and the cold allodynia in the CCI model for, both for rats and gerbils. Drugs with a proven activity in humans, used as reference compounds, also showed good pharmacological activity in this animal study.
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Affiliation(s)
- Kris C P Vissers
- Department of Anesthesiology, Pain and Palliative Medicine, Radboud University, Nijmegen, The Netherlands.
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Connor FL, Di Lorenzo C. Chronic intestinal pseudo-obstruction: assessment and management. Gastroenterology 2006; 130:S29-36. [PMID: 16473068 DOI: 10.1053/j.gastro.2005.06.081] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2004] [Accepted: 06/06/2005] [Indexed: 12/21/2022]
Affiliation(s)
- Frances L Connor
- Division of Pediatric Gastroenterology, Royal Children's Hospital, Herston, Australia
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Granados-Soto V, Argüelles CF. Synergic Antinociceptive Interaction between Tramadol and Gabapentin after Local, Spinal and Systemic Administration. Pharmacology 2005; 74:200-8. [PMID: 15886505 DOI: 10.1159/000085700] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Accepted: 03/10/2005] [Indexed: 01/29/2023]
Abstract
The possible interaction between tramadol and gabapentin on formalin-induced nociception in the rat was assessed. Tramadol, gabapentin or a fixed-dose ratio combination of gabapentin and tramadol were administered peripherally, spinally and orally to rats, and the antinociceptive effect was determined in the 1% formalin test. Isobolographic analyses were used to define the nature of the interactions between drugs. Tramadol, gabapentin and tramadol-gabapentin combinations produced a dose-dependent antinociceptive effect when administered locally, spinally or orally. ED30 values were estimated for the individual drugs and isobolograms were constructed. Theoretical ED30 values for the combination estimated from the isobolograms were 126.8 +/- 11.1 microg/paw, 23.1 +/- 2.6 microg/rat, and 2.23 +/- 0.32 mg/kg for the local, intrathecal and oral routes, respectively. These values were significantly higher than the actually observed ED30 values which were 13.3 +/- 2.1 microg/paw, 8.1 +/- 0.6 microg/rat and 0.71 +/- 0.10 mg/kg, indicating a synergistic interaction. Although efficacy was not improved, local peripheral administration resulted in the highest increase in potency, being about tenfold. Spinal and systemic administration increased potency threefold. Data indicate that low doses of the tramadol-gabapentin combination can interact synergistically to reverse formalin-induced nociception and may represent a therapeutic advantage for clinical treatment of inflammatory pain.
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Affiliation(s)
- Vinicio Granados-Soto
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Coapa, Mexico.
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&NA;. Gabapentin in postherpetic neuralgia. DRUGS & THERAPY PERSPECTIVES 2004. [DOI: 10.2165/00042310-200420050-00003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Vissers K, Hoffmann V, Geenen F, Biermans R, Meert T. Is the Second Phase of the Formalin Test Useful to Predict Activity in Chronic Constriction Injury Models? A Pharmacological Comparison in Different Species. Pain Pract 2003; 3:298-309. [PMID: 17166125 DOI: 10.1111/j.1530-7085.2003.03033.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study presents data of several reference drugs in rats and gerbils for both the second phase of the formalin test and the cold allodynia in animals with a constriction injury of the sciatic nerve. A pharmacological validation of the formalin test and the CCI model in gerbils was performed. It was evaluated whether the second phase of the formalin test could be used as a pharmacological screening to predict outcome in the cold plate test in CCI animals. Male Sprague Dawley and Wistar rats and male gerbils were used for both tests. For the formalin test, animals were injected in the right hind paw (5% formalin rat: 0.05 microl; gerbil: 0.01 microl) and flinching and licking or biting were recorded. For CCI testing, a Bennett operation was performed on the left hind paw 7 days before testing. Cold plate allodynia was evaluated before and after drug treatment. In rats, a good correlation between both test conditions for morphine, fentanyl, MK-801 and flunarizine was found. Clonidine tends to have more activity in the second phase of the formalin test, whereas baclofen, tramadol, amitryptiline, ketamine and topiramate demonstrate to be more active in the cold plate. In gerbils, a good correlation between both test conditions for fentanyl and ketoprofen was found. Tramadol and CP-96345 tend to have more activity in the second phase of the formalin test, whereas morphine, SR-48968, SR-142801 and R116301 demonstrates to be more active in the cold plate test. In the present acute test conditions, there is a correlation in the pharmacological activity in rats and gerbils for the tested compounds a correlation between the second phase of the formalin test and the cold allodynia in CCI animals is found. Comparing to human data the screening drugs tested in this study show a correlation between animal and human studies in these specific circumstances. Further validation studies are needed to make these correlations clinical applicable.
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Affiliation(s)
- K Vissers
- Multidisciplinary Pain Center, Ziekenhuis Oost-Limburg, Genk, Belgium.
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Affiliation(s)
- Daniel A Shoskes
- Department of Urology, Section of Renal Transplantation, Cleveland Clinic Florida, 2950 Cleveland Clinic Blvd., Weston, FL 33331, USA.
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Abstract
Tricyclic antidepressants have been used to manage pain for several decades, and are superior treatments for some patients suffering from neuropathic pain. Unfortunately, older antidepressants have dose-limiting side effects that can lead to drug intolerance. The most common are anticholinergic side effects, although some patients experience sexual dysfunction. Cognitive impairment, sedation, and orthostatic hypotension also are relatively common. Taking an overdose of tricyclic antidepressants can be lethal in overdose. Several weeks of therapy may be required before antinociception occurs, but tricyclic antidepressants in optimal doses appear to be the most effective treatment for neuropathic pain; this is supported by systematic reviews comparing them with other agents. Newer medications such as atypical antidepressants and anticonvulsants may be overtaking older antidepressants, but they should not be overlooked as important options for the management of pain.
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Affiliation(s)
- Lori Reisner
- University of California, San Francisco, Department of Clinical Pharmacy, Box 0622, San Francisco, CA 94143, USA.
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