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Paterson LM, Barker D, Cro S, Mozgunov P, Phillips R, Smith C, Nahar L, Paterson S, Lingford-Hughes AR. FORWARDS-1: an adaptive, single-blind, placebo-controlled ascending dose study of acute baclofen on safety parameters in opioid dependence during methadone-maintenance treatment-a pharmacokinetic-pharmacodynamic study. Trials 2022; 23:880. [PMID: 36258248 PMCID: PMC9579625 DOI: 10.1186/s13063-022-06821-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/05/2022] [Indexed: 11/17/2022] Open
Abstract
Background Treatment of opiate addiction with opiate substitution treatment (e.g. methadone) is beneficial. However, some individuals desire or would benefit from abstinence but there are limited options to attenuate problems with opiate withdrawal. Preclinical and preliminary clinical evidence suggests that the GABA-B agonist, baclofen, has the desired properties to facilitate opiate detoxification and prevent relapse. This study aims to understand whether there are any safety issues in administering baclofen to opioid-dependent individuals receiving methadone. Methods Opiate-dependent individuals (DSM-5 severe opioid use disorder) maintained on methadone will be recruited from addiction services in northwest London (NHS and third sector providers). Participants will be medically healthy with no severe chronic obstructive pulmonary disease or type 2 respiratory failure, no current dependence on other substances (excluding nicotine), no current severe DSM-5 psychiatric disorders, and no contraindications for baclofen or 4800 IU vitamin D (placebo). Eligible participants will be randomised in a 3:1 ratio to receive baclofen or placebo in an adaptive, single-blind, ascending dose design. A Bayesian dose-escalation model will inform the baclofen dose (10, 30, 60, or 90 mg) based on the incidence of ‘dose-limiting toxicity’ (DLT) events and participant-specific methadone dose. A range of respiratory, cardiovascular, and sedative measures including the National Early Warning Score (NEWS2) and Glasgow Coma Scale will determine DLT. On the experimental day, participants will consume their usual daily dose of methadone followed by an acute dose of baclofen or placebo (vitamin D3) ~ 1 h later. Measures including oxygen saturation, transcutaneous CO2, respiratory rate, QTc interval, subjective effects (sedation, drug liking, craving), plasma levels (baclofen, methadone), and adverse events will be obtained using validated questionnaires and examinations periodically for 5 h after dosing. Discussion Study outcomes will determine what dose of baclofen is safe to prescribe to those receiving methadone, to inform a subsequent proof-of-concept trial of the efficacy baclofen to facilitate opiate detoxification. To proceed, the minimum acceptable dose is 30 mg of baclofen in patients receiving ≤ 60 mg/day methadone based on the clinical experience of baclofen’s use in alcoholism and guidelines for the management of opiate dependence. Trial registration Clinicaltrials.gov NCT05161351. Registered on 16 December 2021. Supplementary Information The online version contains supplementary material available at 10.1186/s13063-022-06821-9.
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Affiliation(s)
- L M Paterson
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK.
| | - D Barker
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
| | - S Cro
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - P Mozgunov
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - R Phillips
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - C Smith
- Imperial Clinical Trials Unit, Imperial College London, London, UK
| | - L Nahar
- Toxicology Unit, Imperial College London, London, UK
| | - S Paterson
- Toxicology Unit, Imperial College London, London, UK
| | - A R Lingford-Hughes
- Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
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Durant CF, Paterson LM, Turton S, Wilson SJ, Myers JFM, Muthukumaraswamy S, Venkataraman A, Mick I, Paterson S, Jones T, Nahar LK, Cordero RE, Nutt DJ, Lingford-Hughes A. Using Baclofen to Explore GABA-B Receptor Function in Alcohol Dependence: Insights From Pharmacokinetic and Pharmacodynamic Measures. Front Psychiatry 2018; 9:664. [PMID: 30618857 PMCID: PMC6302106 DOI: 10.3389/fpsyt.2018.00664] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/19/2018] [Indexed: 12/20/2022] Open
Abstract
Background: The role of GABA-B neurotransmission in addiction has recently received increased attention, with clinical trials indicating that baclofen, a GABA-B receptor agonist, may reduce alcohol consumption, craving and promote abstinence. However, the optimal dose to treat alcohol dependence is unclear with patients requesting and tolerating much higher doses of baclofen, compared with other clinical uses. We assessed the pharmacokinetics and pharmacodynamics (PK/PD) of baclofen to provide insight into GABA-B sensitivity in this patient group, relative to controls. Methods: Male healthy volunteers (controls, n = 12) and abstinent alcohol dependent individuals (AD, n = 8) received single oral doses of baclofen or placebo in a 3-way crossover design. Controls received placebo/10 mg/60 mg baclofen in a randomized, double-blind design, AD received placebo/60 mg/90 mg baclofen in a single-blind design. PK/PD measures were recorded at baseline and multiple time-points up to 6 h post-dosing, including plasma baclofen, plasma growth hormone (GH), Subjective High Assessment Scale (SHAS) and biphasic alcohol effects scale (BAES). Repeated measures ANOVA analysis explored "change from baseline" dose, time, group, and interaction effects, t-tests compared peak effects. Results: Dose-dependent effects of baclofen on PK and PD measures were observed in both control and AD groups. Whilst there were no significant group differences in any baclofen PK parameters (t 1/2, t max , C max , AUC), marked differences in PD effects were clearly evident. In controls, 60 mg baclofen significantly increased total SHAS and BAES scores, and significantly increased plasma GH levels compared with placebo, with peak effects at 60-120 min, in line with its PK profile. In AD, 60 mg baclofen had limited effects on these parameters; SHAS scores, BAES scores and plasma GH levels were significantly blunted compared with controls (significant group*time interactions P = 0.0014, 0.0015 and P < 0.0001, respectively). Conclusions: Our study shows blunted sensitivity to baclofen in AD relative to controls, with no difference in PK suggesting a lower GABA-B receptor sensitivity. This may explain why higher baclofen doses are requested and tolerated in the treatment of alcohol dependence. Our data has implications for choice of dose in future clinical trials in AD and possibly other substances of dependence.
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Affiliation(s)
- Claire F Durant
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Louise M Paterson
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Sam Turton
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Susan J Wilson
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - James F M Myers
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | | | - Ashwin Venkataraman
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Inge Mick
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Susan Paterson
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - Tessa Jones
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Limon K Nahar
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - Rosa E Cordero
- Centre for Brain Science, University of Auckland, Auckland, New Zealand
| | - David J Nutt
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
| | - Anne Lingford-Hughes
- Neuropsychopharmacology Unit, Division of Brain Sciences, Department of Medicine, Centre for Psychiatry, Imperial College London, London, United Kingdom
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Bauman WA, La Fountaine MF, Cirnigliaro CM, Kirshblum SC, Spungen AM. Low-dose baclofen therapy raised plasma insulin-like growth factor-1 concentrations, but not into the normal range in a predictable and sustained manner in men with chronic spinal cord injury. J Spinal Cord Med 2013; 36:476-82. [PMID: 23941795 PMCID: PMC3739897 DOI: 10.1179/2045772312y.0000000061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVE To evaluate, whether once-daily oral baclofen administration increases and/or sustains plasma insulin-like growth factor-1 (IGF-1) concentration in 11 men with chronic spinal cord injury (SCI) and IGF-1 deficiency (i.e. <250 ng/ml). DESIGN Prospective, open-label, dose titration study. Baclofen was administered at 20 mg/day for 8 weeks; then increased to 40 mg/day for another 8 weeks. Plasma IGF-1 and self-reported side effects were measured at baseline and every other week for the duration of the study. RESULTS The subjects were 43 ± 12 years old, had duration of injury of 20 ± 12 years; eight subjects had a complete motor injury, and eight had paraplegia. Nine of 11 subjects completed the 20 mg/day treatment and 5 subjects completed the 40 mg/day treatment. Plasma IGF-1 levels improved with each baclofen dose; however, only one subject increased from baseline and remained above the targeted physiological range of 250 ng/ml throughout treatment. A significant increase in IGF-1concentration was observed between baseline and week 2 (154 ± 63 vs. 217 ± 69 ng/ml; P < 0.05), weeks 8 and 10 (188 ± 95 vs. 228 ± 93 ng/ml; P < 0.05), and weeks 8 and 16 (188 ± 95 vs. 259 ± 92 ng/ml; P < 0.05). No serious side effects were observed at 20 mg/day; the 40 mg/day dose was less well tolerated. CONCLUSION Baclofen was not effective at sustaining plasma IGF-1 concentrations in the physiological range in men with chronic SCI.
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Affiliation(s)
- William A. Bauman
- VA RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, USA; Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA; Department of Medicine, The Mount Sinai School of Medicine, New York, NY, USA; and Department of Rehabilitation Medicine, The Mount Sinai School of Medicine, New York, NY, USA,Correspondence to: William A. Bauman, MD, National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, 130 West Kingsbridge Road, Bronx, NY 10468.
| | - Michael F. La Fountaine
- VA RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, USA; and Department of Physical Therapy, School of Health and Medical Sciences, Seton Hall University, South Orange, NJ, USA
| | - Christopher M. Cirnigliaro
- VA RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, USA
| | - Steven C. Kirshblum
- Kessler Institute for Rehabilitation, West Orange, NJ, USA; and Department of Physical Medicine and Rehabilitation, University of Medicine and Dentistry of New Jersey, Newark, NJ, USA
| | - Ann M. Spungen
- VA RR&D National Center of Excellence for the Medical Consequences of Spinal Cord Injury, James J. Peters VA Medical Center, Bronx, NY, USA; Medical Service, James J. Peters VA Medical Center, Bronx, NY, USA; Department of Medicine, The Mount Sinai School of Medicine, New York, NY, USA; and Department of Rehabilitation Medicine, The Mount Sinai School of Medicine, New York, NY, USA
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Giustina A, Veldhuis JD. Pathophysiology of the neuroregulation of growth hormone secretion in experimental animals and the human. Endocr Rev 1998; 19:717-97. [PMID: 9861545 DOI: 10.1210/edrv.19.6.0353] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
During the last decade, the GH axis has become the compelling focus of remarkably active and broad-ranging basic and clinical research. Molecular and genetic models, the discovery of human GHRH and its receptor, the cloning of the GHRP receptor, and the clinical availability of recombinant GH and IGF-I have allowed surprisingly rapid advances in our knowledge of the neuroregulation of the GH-IGF-I axis in many pathophysiological contexts. The complexity of the GHRH/somatostatin-GH-IGF-I axis thus commends itself to more formalized modeling (154, 155), since the multivalent feedback-control activities are difficult to assimilate fully on an intuitive scale. Understanding the dynamic neuroendocrine mechanisms that direct the pulsatile secretion of this fundamental growth-promoting and metabolic hormone remains a critical goal, the realization of which is challenged by the exponentially accumulating matrix of experimental and clinical data in this arena. To the above end, we review here the pathophysiology of the GHRH somatostatin-GH-IGF-I feedback axis consisting of corresponding key neurotransmitters, neuromodulators, and metabolic effectors, and their cloned receptors and signaling pathways. We propose that this system is best viewed as a multivalent feedback network that is exquisitely sensitive to an array of neuroregulators and environmental stressors and genetic restraints. Feedback and feedforward mechanisms acting within the intact somatotropic axis mediate homeostatic control throughout the human lifetime and are disrupted in disease. Novel effectors of the GH axis, such as GHRPs, also offer promise as investigative probes and possible therapeutic agents. Further understanding of the mechanisms of GH neuroregulation will likely allow development of progressively more specific molecular and clinical tools for the diagnosis and treatment of various conditions in which GH secretion is regulated abnormally. Thus, we predict that unexpected and enriching insights in the domain of the neuroendocrine pathophysiology of the GH axis are likely be achieved in the succeeding decades of basic and clinical research.
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Affiliation(s)
- A Giustina
- Department of Internal Medicine, University of Brescia, Italy
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Gerra G, Ferri M, Zaimovic A, Giucastro G, Palladino M, Sartori R, Delsignore R, Maestri D, Marzocchi G, Brambilla F. GABAergic function in detoxified heroin addicts: relationship to anxiety disorders. Psychiatry Res 1998; 77:89-96. [PMID: 9541144 DOI: 10.1016/s0165-1781(97)00147-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The function of the GABAergic system was examined in 20 subjects with heroin dependence and abuse, 2 months after detoxification, and in 10 healthy volunteers, by measuring the growth hormone (GH) response to a challenge with the GABA B receptor agonist baclofen. Ten heroin addicts had comorbid anxiety disorder (Group A), while the other ten had heroin addiction uncomplicated by Axis I and II psychopathologies (Group B). GH responses to baclofen stimulation of Group A patients were significantly blunted, while those of Group B subjects did not differ from responses of healthy volunteers. Our data show that the function of the GABAergic system is impaired only in heroin addicts with comorbid anxiety disorders (anxious cluster), suggesting that the GABA system is not persistently influenced by prolonged exposure to opioid receptor stimulation.
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Affiliation(s)
- G Gerra
- Centro Studi Farmacotossicodipendenze, Ser.T., Azienda USL, Parma, Italy
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Davis LL, Trivedi M, Choate A, Kramer GL, Petty F. Growth hormone response to the GABAB agonist baclofen in major depressive disorder. Psychoneuroendocrinology 1997; 22:129-40. [PMID: 9203224 DOI: 10.1016/s0306-4530(96)00048-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Growth hormone (GH) response to the gamma-aminobutyric acid B receptor agonist, baclofen, was measured in 16 male patients with major depressive disorder and in 16 age-matched healthy male controls. No significant differences were found in the GH response to baclofen between the depressed patients and controls. On repeat testing, the GH response to baclofen showed significant retest reliability in both groups. There was no significant correlation between serum baclofen levels and the GH response to baclofen. Age significantly correlated with GH response, with older subjects having lower GH response to baclofen. These data do not suggest that a blunted GH response to baclofen. represents a specific neuroendocrine feature of major depression.
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Affiliation(s)
- L L Davis
- Veterans Affairs Medical Center, Dallas, TX 75216, USA.
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Davis LL, Trivedi M, Kramer GL, Rush AJ, Orsulak PJ, Akers L, Petty F. Growth hormone response to baclofen: a comparison of 10-mg and 20-mg doses in healthy men. Psychiatry Res 1996; 60:41-7. [PMID: 8852867 DOI: 10.1016/0165-1781(96)02874-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Growth hormone (GH) response and baclofen levels were measured in seven healthy adult men following a 10-mg and a 20-mg dose of oral baclofen (gamma-aminobutyric acidB agonist) to determine the preferred dose in baclofen challenge studies. Multivariate analysis of variance (ANOVA) with repeated measures revealed no differences between the doses. However, when a univariate ANOVA with repeated measures was performed for each dose, the 10-mg dose showed no significant GH response over time, whereas the 20-mg dose showed a significant GH response over time. The average delta GH (change in GH from baseline) was 7.84 ng/ml (SD = 10.17) for the 10-mg dose and 3.34 ng/ml (SD = 3.64) for the 20-mg dose. The variability in the delta GH response to the 10-mg dose was significantly greater than the response to the 20-mg dose of baclofen. This variance in GH response was not explained by the differences in serum baclofen levels. Thus, a 20-mg baclofen dose appears to be preferable to a 10 mg-dose in baclofen challenge studies.
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Affiliation(s)
- L L Davis
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, USA
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Macdonald S, Corrigan FM, Gaskell DF, French M. Enhanced GABAb receptor-mediated transmission in alcohol-dependence syndrome. J Psychopharmacol 1996; 10:321-3. [PMID: 22302982 DOI: 10.1177/026988119601000412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have studied the GABAb receptor-mediated neurotransmissions of alcoholic patients by administering baclofen 10 mg orally and measuring the growth hormone (GH) response. There was a minimal GH response to the baclofen in one of eight control subjects and a greater GH response in 11 of the 16 alcoholic patients. There is thus evidence for increased transmission at the GABAb receptor in detoxified patients with alcohol-dependence syndrome.
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Affiliation(s)
- S Macdonald
- Argyll and Bute Hospital, Lochgilphead, Argyll PA318LD
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