Robertson, Kelvin Lee (2018) Pregabalin and gabapentin for the management of chronic sciatica: determining utility, effect on functioning capacity, quality of life and clinical outcome. PhD thesis, James Cook University.

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Abstract

Background: Pain is a major clinical problem, the true prevalence of which is difficult to estimate as it encompasses a variety of disorders. Sciatica is considered a type of neuropathic pain (NP) characterised by severe low back pain radiating down the leg to below the knee. Chronic sciatica (CS) is sciatica lasting longer than three months. There are few clinical guidelines for treating of CS, reflecting a gap in quality evidence for effective therapies. Recently, two medications gabapentin (GBP) and pregabalin (PGB) have been used in the management of CS. Evidence for their usage is limited with no direct, high quality research to determine if one is superior to the other. This research answers that question and helps guide clinicians as to the best treatment option for CS.

Methods: The thesis includes a literature review to gauge current management of CS with PGB and GBP. The work uses a mixed-methods approach to gain evidence on efficacy, disability and personality traits which will guide clinician's choice of either GBP or PGB. A mix of methods was chosen, to capture patient's treatment experiences more broadly and not simply being restricted to symptom relief. Anecdotal evidence suggests a variable response to either drug, both in terms of efficacy and adverse events (AEs). However, we are unsure at what point the balance of benefits against AEs tips and patients make the decision to abandon treatment. To gather this information and draw conclusions regarding the optimal treatment for patients with CS, this project collects background information on patient's perceptions related to treatment, and conducts a novel randomised controlled trial to determine head to head which treatment is more efficacious. We set out to establish whether one drug has a superior profile to the other and if there are any other differences in treatment outcomes.

Hypothesis: We hypothesise that there are differences between the drugs, where (1) one drug (PGB) has a superior profile in pain and disability reduction, as well as (2) frequency and severity of adverse events.

Results: Retrospective data showed AEs to be a limiting factor for treatment outcomes and compliance when GBP was added to a first line agent. The clinical trial reported here showed that, while PGB and GBP were both significantly efficacious in reducing pain intensity in patients with CS, GBP was superior when compared 'head-to-head'. Moreover, GBP was associated with fewer and less severe AEs. Neither drug was superior when compared 'head-to-head' for reducing disability in our study group. Our exploratory study on personality traits showed that patients with a predominantly external self-control had worse outcomes. Specifically, an external self-control resulted in lower pain severity reductions especially with PGB. Moreover, PGB alone demonstrated a high, and statistically significant, positive correlation with external self-control resulting in higher pain values for patients displaying this personality trait. There were no notable differences between drugs when personality and disability severity were compared.

Conclusion: This research makes a significant original contribution to the literature by addressing a key gap regarding the utilisation of pain medication for CS, namely with PGB and GBP. We found that GBP was superior to PGB for reducing pain severity and for being associated with fewer and less severe AEs. Moreover, our results show having a personality trait of external locus of self-control, negatively effects treatment outcomes with PGB. Our findings provide a body of evidence which can formally guide treatment decisions for patients with CS considering pain severity, disability severity, AEs and personality.

Item ID:	58881
Item Type:	Thesis (PhD)
Keywords:	Pregabalin, Gabapentin, Pharmacy, Clinical Trial, Protocol, Sciatica, Chronic Sciatica, Neuropathic Pain
Related URLs:	https://researchonline.jcu.edu.au/41482/ https://researchonline.jcu.edu.au/49234/ https://researchonline.jcu.edu.au/53311/ https://researchonline.jcu.edu.au/57029/
Copyright Information:	Copyright © 2018 Kelvin Lee Robertson.
Additional Information:	Publications arising from this thesis are available from the Related URLs field. The publications are: Chapter 2: Robertson, Kelvin, Marshman, Laurence A.G., and Plummer, David (2016) Pregabalin and gabapentin for the treatment of sciatica. Journal of Clinical Neuroscience, 26. pp. 1-7. Chapter 3: Robertson, Kelvin L., and Marshman, Laurence A.G. (2016) Gabapentin superadded to a pre-existent regime containing amytriptyline for chronic sciatica. Pain Medicine, 17 (11). pp. 2095-2099. Chapter 4: Robertson, Kelvin, Marshman, Laurence A.G., Hennessy, Maria, Harriss, Linton, and Plummer, David (2018) Pregabalin versus gabapentin in the treatment of sciatica: study protocol for a randomised, double-blind, cross-over trial (PAGPROS). Trials, 19 (21). Chapter 5: Robertson, Kelvin, Marshman, Laurence A.G., Plummer, David, and Downs, Elena (2019) Effect of gabapentin vs pregabalin on pain intensity in adults with chronic sciatica: a randomized clinical trial. JAMA Neurology, 76 (1). pp. 28-34.
Date Deposited:	09 Jul 2019 22:14
FoR Codes:	11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110904 Neurology and Neuromuscular Diseases @ 20% 11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110999 Neurosciences not elsewhere classified @ 40% 11 MEDICAL AND HEALTH SCIENCES > 1115 Pharmacology and Pharmaceutical Sciences > 111503 Clinical Pharmacy and Pharmacy Practice @ 40%
SEO Codes:	92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920111 Nervous System and Disorders @ 80% 92 HEALTH > 9204 Public Health (excl. Specific Population Health) > 920412 Preventive Medicine @ 20%
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