Gabapentin Supplemented With Ropivacain Block of Trigger Points Improves Pain Control and Quality of Life in Trigeminal Neuralgia Patients When Compared With Gabapentin Alone

Considerations When Using Gabapentinoids to Treat Trigeminal Neuralgia: A Review

Despite the exemplary efficacy of voltage-gated sodium channel blockers as a first-line treatment of trigeminal neuralgia, the pharmacological management of this excruciating facial pain condition remains a major issue, as these first-line drugs produce intolerable side effects in a significant portion of patients. In addition, in patients with concomitant continuous pain, the efficacy of these drugs may drop, thus suggesting the opportunity to test the efficacy of different drug categories. The aim of this review is to provide current, evidence-based, knowledge about the use of gabapentin and other α2δ ligands in patients with trigeminal neuralgia. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews and the Clinical Trials database (ClinicalTrials.gov), considering publications up to April 2023. Two authors independently selected studies for inclusion and data extraction. The efficacy of α2δ ligands, gabapentin and pregabalin, has been assessed in seven controlled or open-label studies. Despite the low quality of evidence, the favorable tolerability profile and the possible action on concomitant continuous pain make this drug category of interest for future trials in trigeminal neuralgia.

The efficacy and safety of gabapentin vs. carbamazepine in patients with primary trigeminal neuralgia: A systematic review and meta-analysis

Background

Drug therapy is the most commonly used treatment for primary trigeminal neuralgia (PTN), in which carbamazepine is the first-line drug. Recently, the anti-epileptic drug gabapentin has also been widely used in patients with PTN, but whether it can be used as a substitute for carbamazepine still needs to be verified. Our study aimed to assess the safety and efficacy of gabapentin vs. carbamazepine as a treatment for PTN.

Methods

We searched seven electronic databases for studies published as of 31 July 2022. All randomized controlled trials (RCTs) of gabapentin vs. carbamazepine on patients with PTN that met the inclusion criteria were included. Meta-analysis was conducted using Revman 5.4 and Stata 14.0, in which forest plots, funnel plots, and sensitivity analysis were performed. Mean difference (MD) and odds ratio (OR) with 95% confidence intervals (CIs) were used for the measurement indicators of continuous and categorical variables, respectively.

Results

A total of 18 RCTs with 1,604 patients were eventually identified. The meta-analysis showed that compared with the carbamazepine group, the gabapentin group significantly improved the effective rate (OR = 2.02, 95% CI 1.56 to 2.62, P < 0.001), reduced the adverse event rate (OR = 0.28, 95% CI 0.21 to 0.37, P < 0.001), and improved the visual analog scale (VAS) score (MD = -0.46, 95% CI -0.86 to -0.06, P = 0.03). Although the funnel plot showed evidence of publication bias, the sensitivity analysis revealed the stability of the results.

Conclusion

The current evidence showed that gabapentin may be superior to carbamazepine in relation to efficacy and safety in patients with PTN. It is crucial that more RCTs are conducted to confirm the conclusion in the future.

Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a rare neuropathic pain disorder characterized by recurrent, paroxysmal episodes of short-lasting severe electric shock-like pain along the sensory distribution of the trigeminal nerve. Recent classification systems group TN into 3 main categories depending on the underlying pathophysiology. This article will present a case history and review the epidemiology, diagnostic criteria, classification, clinical features, diagnostic investigations, pathophysiology, and management of TN.

Effectiveness, Safety, and Predictors of Response to 5% Lidocaine-Medicated Plaster for the Treatment of Patients With Trigeminal Neuralgia: A Retrospective Study

BACKGROUND

Whether 5% lidocaine-medicated plaster (LMP) is a valuable therapeutic option for the treatment of trigeminal neuralgia (TN) is worth exploring. If LMP is proven effective for TN, positive predictors of the analgesic effects of LMP warrant further investigation.

OBJECTIVE

To evaluate the efficacy and safety of LMP for the treatment of TN, and to explore the predictive factors for the treatment efficacy of LMP.

METHODS

This is a retrospective and observational study. We analyzed the efficacy of LMP for the treatment of TN between March 2019 and January 2022. The follow-up time was approximately 2 weeks, 1 month, 2 months, and 3 months after LMP treatment. The LMP response was considered the Barrow Neurological Institute (BNI) score of I to III and an improvement in BNI of at least I grade from pretreatment baseline. Univariable and multivariable logistic analyses were performed to identify the predictive factors for LMP response.

RESULTS

A total of 103 patients were included and analyzed in this study. LMP was effective in some TN patients, with an efficacy rate of 21.4%, 21.4%, 18.4%, and 16.5% after 2 weeks, 1 month, 2 months, and 3 months of LMP treatment, respectively. The overall adverse event rate associated with LMP was 5.8%, and the reported adverse events were all skin reactions. Facial trigger points (odds ratio [OR] = 0.25, 95% confidence interval [CI] = 0.07-0.86, P = 0.03) and a lower BNI score (OR = 0.37, 95% CI = 0.07-0.87, P = 0.01) were identified as potential predictors for initial efficacy (2-week follow-up) of LMP treatment.

CONCLUSIONS AND RELEVANCE

LMP has been shown to provide effective and sustained analgesia in some TN patients with minimal risk of systemic adverse reactions. Patients with facial trigger points and mild to moderate pain are more likely to benefit from LMP treatment. Our data suggest that LMP may be an effective treatment option for patients with the aforementioned characteristics of TN.

Pharmacotherapeutic management of trigeminal neuropathic pain: an update

INTRODUCTION

Guidelines recommend a number of pharmacotherapeutic options used as monotherapy or in combination with others for treating the pain of trigeminal neuropathy.

AREAS COVERED

The authors examine the pharmacotherapeutic options for treating trigeminal neuralgia and supporting evidence in the literature. Guidelines reported the most effective treatment for trigeminal neuropathy, in particular trigeminal neuralgia, appears to be carbamazepine or oxcabazepine, but side effects can be treatment limiting. Lamotrigine and gabapentin are also recommended in guidance. In real-world clinical practice, baclofen, cannabinoids, eslicarbazepine, levetiracetam, brivaracetam, lidocaine, misoprostol, opioids, phenytoin, fosphenytoin, pimozide, sodium valproate, sumatriptan, tizanidine, tocainide, tricyclic antidepressants, and vixotrigine are sometimes used, either as monotherapy or in combination. The relatively small patient population has limited the number of large-scale studies and there is limited evidence on which to base prescribing choices.

EXPERT OPINION

While there is no optimal pharmacotherapy for treating trigeminal neuropathy, advancements in our understanding of the underlying mechanisms of this condition and drug development indicate promise for NaV inhibitors, despite the fact that not all patients respond to them and they may have potentially treatment-limiting side effects. Nevertheless, better understanding of NaV channels may be important avenues for future drug development for trigeminal neuropathy.

A Review of Medical and Surgical Options for the Treatment of Facial Pain

Facial pain is a common medical complaint that is easily misdiagnosed. As a result, this pain often goes mistreated. Despite this, there are a variety of pharmacologic, surgical, and neuromodulatory options for the treatment of facial pain. In this review, the authors detail the forms of facial pain and their treatment options. They discuss the common medications used in the first-line treatment of facial pain and the second-line surgical and neuromodulatory options available to patients when pharmacologic options fail.

The Molecular Basis and Pathophysiology of Trigeminal Neuralgia

Trigeminal neuralgia (TN) is a complex orofacial pain syndrome characterized by the paroxysmal onset of pain attacks in the trigeminal distribution. The underlying mechanism for this debilitating condition is still not clearly understood. Decades of basic and clinical evidence support the demyelination hypothesis, where demyelination along the trigeminal afferent pathway is a major driver for TN pathogenesis and pathophysiology. Such pathological demyelination can be triggered by physical compression of the trigeminal ganglion or another primary demyelinating disease, such as multiple sclerosis. Further examination of TN patients and animal models has revealed significant molecular changes, channelopathies, and electrophysiological abnormalities in the affected trigeminal nerve. Interestingly, recent electrophysiological recordings and advanced functional neuroimaging data have shed new light on the global structural changes and the altered connectivity in the central pain-related circuits in TN patients. The current article aims to review the latest findings on the pathophysiology of TN and cross-examining them with the current surgical and pharmacologic management for TN patients. Understanding the underlying biology of TN could help scientists and clinicians to identify novel targets and improve treatments for this complex, debilitating disease.

Trigeminal Neuralgia: Current Approaches and Emerging Interventions

Trigeminal neuralgia (TN) has been described in the literature as one of the most debilitating presentations of orofacial pain. This review summarizes over 150 years of collective clinical experience in the medical and surgical treatment of TN. Fundamentally, TN remains a clinical diagnosis that must be distinguished from other types of trigeminal neuropathic pain and/or facial pain associated with other neuralgias or headache syndromes. What is increasingly clear is that there is no catch-all medical or surgical intervention that is effective for all patients with trigeminal neuralgia, likely reflective of the fact that TN is likely a heterogenous group of disorders that jointly manifests in facial pain. The first-line treatment for TN remains anticonvulsant medical therapy. Patients who fail this have a range of surgical options available to them. In general, microvascular decompression is a safe and effective procedure with immediate and durable outcomes. Patients who are unable to tolerate general anesthesia or whose medical comorbidities preclude a suboccipital craniectomy may benefit from percutaneous methodologies including glycerol or radiofrequency ablation, or both. For patients with bleeding diathesis due to blood thinning medications who are ineligible for invasive procedures, or for those who are unwilling to undergo open surgical procedures, radiosurgery may be an excellent option-provided the patient understands that maximum pain relief will take on the order of months to achieve. Finally, peripheral neurectomies continue to provide an inexpensive and resource-sparing alternative to pain relief for patients in locations with limited economic and medical resources. Ultimately, elucidation of the molecular mechanisms underlying trigeminal neuralgia will pave the way for novel, more effective and less invasive therapies.

Medical Management of Trigeminal Neuralgia

Background

Trigeminal neuralgia (TN) is a painful condition, often leading to poor quality of life.

Objective

The aim of this review was to discuss the various treatment modalities for the medical management of TN.

Materials and Methods

We reviewed the available literature on TN in clinical databases including PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews, with a specific focus on the pharmacological treatment and newer drugs under development for the treatment of TN.

Results

Carbamazepine (CBZ) is the gold standard of treatment for TN. The first-line drugs for the treatment of TN are CBZ and oxcarbazepine (OXC). A proportion of cases (30%) are initially resistant to the first-line drugs. Alternative drugs need to be considered if the first-line drugs are not well tolerated or become ineffective with prolonged therapy. The second-line drugs comprise lamotrigine, baclofen, gabapentin, and pregabalin used as monotherapy or in combination with CBZ/OXC. Botulinum toxin A may be a promising presurgical option. Newer drug like vixotrigine has shown good results in phase two randomized control trials. About 50% of cases develop treatment resistance to oral drugs over the subsequent years of therapy and require surgical options.

Conclusion

The first-line drugs for the treatment of TN (irrespective of the age group or type) are CBZ and OXC. Combination therapy with second-line or other drugs may become necessary with poor response to CBZ/OXC, or if adverse events occur. Patients should be offered surgical options if there is poor response or tolerance to the medical therapy.

Neuromodulators for Atypical Facial Pain and Neuralgias: A Systematic Review and Meta-Analysis

OBJECTIVE

To evaluate the effectiveness of neuromodulating agents for the management of atypical facial pain and primary facial neuralgias.

METHODS

We searched MEDLINE, Embase, CINAHL, and ClinicalTrials.gov databases for original research articles that examine the effectiveness and adverse reactions of pharmacologic therapy for the treatment of trigeminal neuralgia and atypical facial pain. Studies that included surgical interventions for atypical facial pain or facial pain secondary to other causes were excluded. Meta-analysis was conducted for reductions in symptom scores and adverse effects.

RESULTS

Of 3,409 articles screened, 73 full-text articles were included, consisting of 45 observational studies and 29 randomized controlled trials. Twenty-four different pharmacological agents were assessed; carbamazepine was the most frequently studied while botulinum toxin A demonstrated the highest consistency in reduction of symptom scores. Pooled estimate of three randomized controlled trials revealed that patients with trigeminal neuralgia who received botulinum toxin A had higher odds (odds ratio 7.46; 95% CI 3.53-15.78) of achieving a ≥50% reduction in visual analogue scale scores compared to controls. Pooled estimate of 15 observational studies showed that three-fourths of patients with trigeminal neuralgia who received carbamazepine experienced clinically significant pain reduction (prevalence proportion 0.75; 95% CI 0.66-0.83).

CONCLUSIONS

Patients receiving botulinum toxin A for trigeminal neuralgia had higher odds of achieving ≥50% reduction in pain scores. A significant proportion of patients with trigeminal neuralgia experienced positive response to carbamazepine. There was moderate evidence for amitriptyline in patients with atypical facial pain. Standardization of outcome reporting would facilitate future quantitative comparisons of therapeutic effectiveness. Laryngoscope, 131:1235-1253, 2021.

Craniofacial neuralgias

While non-headache, non-oral craniofacial neuralgia is relatively rare in incidence and prevalence, it can result in debilitating pain. Understanding the relevant anatomy of peripheral branches of nerves, natural history, clinical presentation, and management strategies will help the clinician better diagnose and treat craniofacial neuralgias. This article will review the nerves responsible for neuropathic pain in periorbital, periauricular, and occipital regions, distinct from idiopathic trigeminal neuralgia. The infratrochlear, supratrochlear, supraorbital, lacrimal, and infraorbital nerves mediate periorbital neuralgia. Periauricular neuralgia may involve the auriculotemporal nerve, the great auricular nerve, and the nervus intermedius. The greater occipital nerve, lesser occipital nerve, and third occipital nerve transmit occipital neuralgias. A wide range of treatment options exist, from modalities to surgery, and the evidence behind each is reviewed.

Treatment Outcomes in Trigeminal Neuralgia-A Systematic Review of Domains, Dimensions and Measures

BACKGROUND

Trigeminal neuralgia (TN) is a painful disorder characterized by sudden electric shock-like pain. It is a rare condition for which multiple treatments are available, including medical and surgical. The best treatment option is yet to be defined, and this is related to the lack of definition in the treatment outcomes and outcome measures. The aim of this systematic review was to summarize all the outcomes and outcomes measures that have been published to date and highlight variability in their use.

METHODS

We have conducted a literature search using a wide range of databases (1946-2019 for medical and 2008-2019 for surgical treatment), for all intervention studies in TN. Four hundred and sixty-seven studies were selected for data extraction on TN classification, data collection method, intervention, and treatment outcomes mapped to the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT guidelines).

RESULTS

Most studies collected data on pain (n = 459) and side effects (n = 386) domains; however, very few collected data on the impact of treatment on physical (n = 46) and emotional functioning (n = 17) and on patient satisfaction (n = 35). There was high variability on outcome measures used for pain relief (n = 10), pain intensity (n = 9), and frequency of pain episodes (n = 3).

CONCLUSIONS

A clear definition of what are the important outcomes for patients with TN is essential. The choice of standardized outcome measures allowing for consistent reporting in TN treatment will allow for comparison of studies and facilitate treatment choice for patients and clinicians thus, improving health outcomes and reducing health care cost.

Trigeminal Neuralgia: Basic and Clinical Aspects

The trigeminal nerve is the largest of all cranial nerves. It has three branches that provide the main sensory innervation of the anterior two-thirds of the head and face. Trigeminal neuralgia (TN) is characterized by sudden, severe, brief, and stabbing recurrent episodes of facial pain in one or more branches of the trigeminal nerve. Pain attacks can occur spontaneously or can be triggered by non-noxious stimuli, such as talking, eating, washing the face, brushing teeth, shaving, a light touch or even a cool breeze. In addition to pain attacks, a proportion of the patients also experience persistent background pain, which along with autonomic signs and prolonged disease duration, represent predictors of worse treatment outcomes. It is now widely accepted that the presence of a neurovascular compression at the trigeminal root entry zone is an anatomic abnormality with a high correlation with classical TN. However, TN may be related to other etiologies, thus presenting different and/or additional features. Since the 1960s, the anticonvulsant carbamazepine is the drug of choice for TN treatment. Although anti-epileptic drugs are commonly used to treat neuropathic pain in general, the efficacy of carbamazepine has been largely limited to TN. Carbamazepine, however, is associated with dose-limiting side-effects, particularly with prolonged usage. Thus, a better understanding and new treatment options are urgently warranted for this rare, but excruciating disease.

Efficacy of gabapentin in the treatment of trigeminal neuralgia: A systematic review of randomized controlled trials

The aim of this systematic review was to determine the efficacy of gabapentin (GBP) in the treatment of pain of  idiopathic trigeminal neuralgia (TN). A comprehensive literature search was conducted using the Cumulative Index of Nursing and Allied Health Literature (EBSCO Industries), Emcare (Ovid), Medline (Ovid), Medline (PubMed), Scopus (Elsevier) and Web of Science (Clarivate Analytics). The inclusion criteria comprised randomized controlled trials of GBP as a monotherapy in the treatment of idiopathic TN in adult participants and publications in English. All other study methodologies were excluded. The search yielded 1472 articles, and after exclusion, 11 full-text articles were eligible for full-text analysis. Only two studies met the inclusion criteria. There is insufficient evidence either to support or refute the efficacy of GBP in the management of idiopathic TN. Therefore, further well-designed placebo-controlled trials are required to confirm the efficacy of GBP in managing TN pain as a single therapy.

A systematic review of rescue analgesic strategies in acute exacerbations of primary trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia (TN) can have a significant impact on wellbeing and quality of life. Limited data exist for treatments that improve TN pain acutely, within 24 h of administration. This systematic review aims to identify effective treatments that acutely relieve TN exacerbations.

METHODS

We searched Medline and Cochrane Central Register of Controlled Trials (CENTRAL) for relevant English language publications. The reference list for all articles was searched for other relevant publications. All studies that satisfied the following PICO criteria were included: (i) Population-adults with acute exacerbation of primary TN symptoms; (ii) Intervention-any medication or intervention with the primary goal of pain relief within 24 h; (iii) Comparator-usual medical care, placebo, sham or active treatment; (iv) Outcome-more than 50% reduction in pain intensity within 24 h of administration.

RESULTS

Of 431 studies, 17 studies were identified that reported immediate results of acute treatment in TN. The evidence suggests that the following interventions may be beneficial: local anaesthetic, mainly lidocaine (ophthalmic, nasal or oral mucosa, trigger point injection, i.v. infusion, nerve block); anticonvulsant, phenytoin or fosphenytoin (i.v. infusion); serotonin agonist, sumatriptan (s.c. injection, nasal). Other referenced interventions with very limited evidence include N-methyl-d-aspartate receptor antagonist (magnesium sulphate infusion) and botulinum toxin (trigger point injection).

CONCLUSIONS

Several treatment options exist that may provide fast and safe relief of TN. Future studies should report on outcomes within 24 h to improve knowledge of the acute analgesic TN treatments.

Injection of ropivacaine combined with pregabalin in a patient with post-traumatic trigeminal neuropathic pain

Introduction: Post-traumatic painful trigeminal neuropathy is a chronic facial pain secondary to trigeminal nerve injury. The treatment of this pain is a therapeutic issue due to the alteration of quality of life that it generates. Observation: A 58-year-old man whose main history of facial trauma has been consulted in the Odontology Department for bilateral trigeminal neuropathic pain that has been evolving for several months. The interrogation revealed continuous pain like electric shocks in the canine areas and daily painful exacerbations. Hyperesthesia and allodynia were found on clinical examination. The patient had received several treatments, oral and local, without significant improvement. As a last resort, injections of ropivacaine every 2 weeks associated with pregabalin (200 mg/day) were performed. At 6 months, there was a clear decrease in the burning sensation and a complete disappearance of painful exacerbations. Discussion: Two studies have recently shown the benefit of the combination of an antiepileptic and a local analgesic in the treatment of classical trigeminal neuralgia, justifying their use in a context of post-traumatic neuropathic pain. Conclusion: Further studies with higher levels of evidence are needed to confirm these preliminary results.

Current and Innovative Pharmacological Options to Treat Typical and Atypical Trigeminal Neuralgia

Trigeminal neuralgia is a representative neuropathic facial pain condition, characterised by unilateral paroxysmal pain in the distribution territory of one or more divisions of the trigeminal nerve, triggered by innocuous stimuli. A subgroup of patients with trigeminal neuralgia [TN (previously defined as atypical TN)] also suffer from concomitant continuous pain, i.e. a background pain between the paroxysmal attacks. The aim of this review is to provide current, evidence-based, knowledge about the pharmacological treatment of typical and atypical TN, with a specific focus on drugs in development. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews and the Clinical Trials database (ClinicalTrials.gov), taking into account publications up to February 2018. Two authors independently selected studies for inclusions, data extraction, and bias assessment. Carbamazepine and oxcarbazepine are the first-choice drugs for paroxysmal pain. When sodium channel blockers cannot reach full dosage because of side effects, an add-on treatment with lamotrigine or baclofen should be considered. In patients with atypical TN, both gabapentin and antidepressants are expected to be efficacious and should be tried as an add-on to oxcarbazepine or carbamazepine. Although carbamazepine and oxcarbazepine are effective in virtually the totality of patients, they are responsible for side effects causing withdrawal from treatment in an important percentage of cases. A new, better tolerated, Nav1.7 selective state-dependent, sodium channel blocker (vixotrigine) is under development. Future trials testing the effect of combination therapy in patients with TN are needed, especially in patients with concomitant continuous pain and in TN secondary to multiple sclerosis.

Pharmacological treatment of trigeminal neuralgia

INTRODUCTION

Unique among the different neuropathic pain conditions, trigeminal neuralgia frequently has an excellent response to some selected drugs, which, on the other hand, often entail disabling side effects. Physicians should be therefore acquainted with the management of these drugs and the few alternative options. Areas covered: This article, based on a systematic literature review, describes the pharmacological options, and indicates the future perspectives for treating trigeminal neuralgia. The article therefore provides current, evidence-based knowledge about the pharmacological treatment of trigeminal neuralgia, and suggests a practical approach to the various drugs, including starting dose, titration and side effects. Expert commentary: Carbamazepine and oxcarbazepine are the reference standard drugs for treating patients with trigeminal neuralgia. They are effective in most patients. The undesired effects however cause withdrawal from treatment or a dosage reduction to an insufficient level in many patients. Sodium channel blockers selective for the sodium channel 1.7 (Nav1.7) receptor, currently under development, might be an alternative, better-tolerated pharmacological option in the next future.

Efficacy and Safety of Gabapentin vs. Carbamazepine in the Treatment of Trigeminal Neuralgia: A Meta-Analysis

To evaluate the safety and efficacy of gabapentin in comparison with carbamazepine in the treatment of trigeminal neuralgia, a meta-analysis of randomized controlled trials was performed. Two reviewers independently selected studies, assessed study quality, and extracted data. Sixteen randomized controlled trials that included 1,331 patients were assessed. The meta-analysis showed that the total effective rate of gabapentin therapy group was similar with carbamazepine therapy group (OR = 1.600, 95% CI 1.185, 2.161, P = 0.002). While the effective rate of gabapentin therapy for 4 weeks was higher than that of carbamazepine therapy (OR = 1.495, 95% CI 1.061, 2.107, P = 0.022, heterogeneity: x² = 7.12, P = 0.625, I² = 0.0%), the life satisfaction improvement is also better in the gabapentin therapy group after a 4-week treatment (SMD = 0.966, 95% CI 0.583, 1.348, P < 0.001). Furthermore, our meta-analysis suggested that the adverse reaction rate of gabapentin therapy group was significantly lower than that of carbamazepine therapy group (OR = 0.312, 95% CI 0.240, 0.407, P < 0.001). In conclusion, present trials comparing gabapentin with carbamazepine are all poor in terms of methodological quality. Based on the available evidence, it is not possible to draw conclusions regarding the efficacy and side effects of gabapentin being superior to carbamazepine.

Combination of pharmacotherapy and lidocaine analgesic block of the peripheral trigeminal branches for trigeminal neuralgia: a pilot study

Classical trigeminal neuralgia (CTN) is treated predominantly by pharmacotherapy but side effects and unsuccessful occurs. The current study was carried out to evaluate the therapeutic effect of combination of pharmacotherapy and lidocaine block. Thirteen patients with CTN managed with pharmacotherapy were recruited and assigned either to no additional treatment (Group I) or to additional analgesic block (Group II). The primary endpoint was the reduction in the frequency of pain episodes in a month assessed at 30 and 90 days. Comparisons of measurements of pain, general health and depression scales were secondary endpoints. The results from the follow-up visits at 30 and 90 days showed the Group II to have larger reduction in the frequency of pain and exhibited a bigger improvement in the scores of the pain, general health and depression scales. The results from this preliminary study suggest a clinical benefit of the combination of pharmacotherapy and lidocaine block.

Evidence-Based Complementary and Alternative Medicine in Inpatient Care

The aim of this report is to provide the reader an overview of the complex therapy currently used within the German health system. Complex therapies in inpatient care in Germany establish the basis for an integrative and interdisciplinary provision of services. They define minimal criteria for the organization of a hospital, enable the integration of different therapeutic approaches, and therefore, lead to an intensive and holistic treatment by a specially trained team. The German model can be viewed as a pilot program for the introduction of integrative patient-centered care in other hospitals around the world.

Effect of 5% Lidocaine Medicated Plaster on Pain Intensity and Paroxysms in Classical Trigeminal Neuralgia

Objective: Trigeminal neuralgia (TN) is a neuropathic pain condition affecting one or more branches of the trigeminal nerve. It is characterized by unilateral, sudden, shock-like, and brief painful attacks, which follow the distribution of trigeminal nerve branches, and with no other accompanying sensorimotor or autonomic signs and symptoms. Current guidelines stipulate which therapies represent first-, second-, and third-line treatments for TN, but there is a consistent mismatch between the therapeutic guidelines and the patient’s preferences and expectations. Case Summary: We report on 2 patients with classical TN in whom conventional drugs for TN were not tolerated. In these patients, treatment with 5% lidocaine medicated plaster (LMP) resulted in reduction of pain intensity and the number of pain paroxysms. Discussion: LMP is known to block the sodium channels on peripheral nerves and may cause a selective and partial block of Aδ and C fibers. According to the TN ignition hypothesis, blockage of peripheral afferents by LMP may reduce pain paroxysms. The effect of LMP may outlast the pharmacokinetics of the drug by reducing pain amplification mechanisms in the central nervous system. LMP has limited or no systemic side effects. Conclusions: LMP may be an effective and well-tolerated treatment option for TN in those patients who do not tolerate or who refuse other therapies. Future randomized controlled studies should better address this issue.

Non-antiepileptic drugs for trigeminal neuralgia

BACKGROUND

Trigeminal neuralgia was defined by the International Association for the Study of Pain as a sudden, usually unilateral, severe, brief, stabbing recurrent pain in the distribution of one or more branches of the fifth cranial nerve. Standard treatment is with anti-epileptic drugs. Non-antiepileptic drugs have been used in the management of trigeminal neuralgia since the 1970s. This is an update of a review first published in 2006 and previously updated in 2011.

OBJECTIVES

To systematically review the efficacy and tolerability of non-antiepileptic drugs for trigeminal neuralgia.

SEARCH METHODS

On 20 May 2013, for this updated review, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2013, Issue 4), MEDLINE (January 1966 to May 2013), EMBASE (January 1980 to May 2013), LILACS (January 1982 to May 2013) and the Chinese Biomedical Retrieval System (1978 to May 2013). We searched clinical trials registries for ongoing trials.

SELECTION CRITERIA

We included double-blind, randomised controlled trials in which the active drug was used either alone or in combination with other non-antiepileptic drugs for at least two weeks.

DATA COLLECTION AND ANALYSIS

Two authors decided which trials fitted the inclusion criteria and independently graded risk of bias. We assessed the quality of the evidence according to the GRADE criteria for this update.

MAIN RESULTS

In this 2013 update, we updated the searches, but identified only two new ongoing studies. The review includes four trials involving 139 participants. The primary outcome measure in each was pain relief. Three trials compared one of the oral non-antiepileptic drugs tizanidine, tocainide or pimozide with carbamazepine. The quality of evidence for all outcomes for which data were available was low. In a trial of tizanidine involving 12 participants (one dropped out due to unrelated disease), one of five participants treated with tizanidine and four of six treated with carbamazepine improved (risk ratio (RR) 0.30, 95% confidence interval (CI) 0.05 to 1.89). Few side effects were noted with tizanidine. For pimozide, there was evidence of greater efficacy than carbamazepine at six weeks. Up to 83% of participants reported adverse effects but these did not lead to withdrawal; the report did not provide comparable data for carbamazepine. Limited data meant that we could not assess the effects of tocainide; however, data from non-randomised studies (not included in this review) indicate that serious haematological adverse events can occur. A trial involving 47 participants compared 0.5% proparacaine hydrochloride eyedrops with placebo but did not show any significant benefits, again according to low-quality evidence. The report did not mention adverse events. The proparacaine trial was at low risk of bias; the other trials were at unclear risk of bias overall.

AUTHORS' CONCLUSIONS

There is low-quality evidence that the effect of tizanidine is not significantly different than that of carbamazepine in treating trigeminal neuralgia. Pimozide is more effective than carbamazepine, although the evidence is of low quality and the data did not allow comparison of adverse event rates. There is also low-quality evidence that 0.5% proparacaine hydrochloride eye drops have no benefit over placebo. Limitations in the data for tocainide prevent any conclusions being drawn. There is insufficient evidence from randomised controlled trials to show significant benefit from non-antiepileptic drugs in trigeminal neuralgia. More research is needed.

Novel design for a phase IIa placebo-controlled, double-blind randomized withdrawal study to evaluate the safety and efficacy of CNV1014802 in patients with trigeminal neuralgia

Background

Trigeminal neuralgia (TN) is a rare severe unilateral facial pain condition. Current guidelines in trigeminal neuralgia management recommend sodium channel blockers – carbamazepine or oxcarbazepine – as the first-line treatment. However, the currently available drugs are often associated with poor tolerability resulting in sub-optimal pain control. CNV1014802 is a novel sodium channel blocker that is being assessed in the treatment of trigeminal neuralgia. Due to the severity of the condition, it is not ethical to conduct a traditional placebo-controlled randomized controlled trial. It is also difficult to use an active control such as carbamazepine, the current gold standard, because of its complex pharmacology and potential for drug interactions.

Methods/Design

The trial uses a randomized withdrawal design to assess efficacy in this rare condition. There is a 21-day open-label phase followed by a randomized 28-day placebo-controlled phase for responders. Thirty patients will be randomized. The primary outcome measure will be pain relief, but secondary measures of quality of life will be of significant importance given the effect of this condition on activities of daily living. Safety and adverse event endpoints are described.

Discussion

There have been very few well-controlled, randomized, placebo-controlled studies in trigeminal neuralgia, and the majority of drugs have had other primary uses. Due to the severity of the pain, minimizing the time a patient is administered placebo was a key factor in designing this study. This study will not only provide data on the efficacy of CNV1014802 in trigeminal neuralgia, but will also provide information on the effectiveness and acceptability of a novel trial design in trigeminal neuralgia.

Trial registration

Trial number NCT01540630

Differential diagnosis of facial pain and guidelines for management

The diagnosis and management of facial pain below the eye can be very different dependant on whether the patient visits a dentist or medical practitioner. A structure for accurate diagnosis is proposed beginning with a very careful history. The commonest acute causes of pain are dental and these are well managed by dentists. Chronic facial pain can be unilateral or bilateral and continuous or episodic. The commonest non-dental pains are temporomandibular disorders (TMDs), especially musculoskeletal involving the muscles of mastication either unilaterally or bilaterally; they may be associated with other chronic pains. A very wide range of treatments are used but early diagnosis, reassurance and some simple physiotherapy is often effective in those with good coping strategies. Dentists will often make splints to wear at night. Neuropathic pain is usually unilateral and of the episodic type; the most easily recognized is trigeminal neuralgia. This severe electric shock like pain, provoked by light touch, responds best to carbamazepine, and neurosurgery in poorly controlled patients. Trauma, either major or because of dental procedures, results in neuropathic pain and these are then managed as for any other neuropathic pain. Red flags include giant cell arteritis which much be distinguished from temporomandibular disorders (TMD), especially in >50 yr olds, and cancer which can present as a progressive neuropathic pain. Burning mouth syndrome is rarely recognized as a neuropathic pain as it occurs principally in peri-menopausal women and is thought to be psychological. Chronic facial pain patients are best managed by a multidisciplinary team.

Refractory trigeminal neuralgia. Non-surgical treatment options

The guidelines on trigeminal neuralgia management published by the American Academy of Neurology (AAN) and the European Federation of Neurological Societies (EFNS) recommended that patients unresponsive to carbamazepine or oxcarbazepine be offered the surgical option. However, because some patients may not be willing to resort to surgery, we searched the literature for treatment in refractory trigeminal neuralgia. We found other oral treatments, intranasal spray, subcutaneous injections, various kinds of peripheral nerve blocks and injections of botulinum toxin. On the basis of the available evidence we suggest that no oral treatment other than carbamazepine or oxcarbazepine is useful. Among the other options, there is increasingly strong evidence that botulinum toxin injections are efficacious and may be offered before surgery or to those unwilling to undergo surgery.

Combination pharmacotherapy for the treatment of neuropathic pain in adults

BACKGROUND

Pharmacotherapy remains an important modality for the treatment of neuropathic pain. However, as monotherapy current drugs are associated with limited efficacy and dose-related side effects. Combining two or more different drugs may improve analgesic efficacy and, in some situations, reduce overall side effects (e.g. if synergistic interactions allow for dose reductions of combined drugs).

OBJECTIVES

This review evaluated the efficacy, tolerability and safety of various drug combinations for the treatment of neuropathic pain.

SEARCH METHODS

We identified randomised controlled trials (RCTs) of various drug combinations for neuropathic pain from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 9 April 2012.

SELECTION CRITERIA

Double-blind, randomised studies comparing combinations of two or more drugs (systemic or topical) to placebo and/or at least one other comparator for the treatment of neuropathic pain.

DATA COLLECTION AND ANALYSIS

Data extracted from each study included: proportion of participants a) reporting ≥ 30% pain reduction from baseline OR ≥ moderate pain relief OR ≥ moderate global improvement; b) dropping out of the trial due to treatment-emergent adverse effects; c) reporting each specific adverse effect (e.g. sedation, dizziness) of ≥ moderate severity. The primary comparison of interest was between study drug(s) and one or both single-agent comparators. We combined studies if they evaluated the same drug class combination at roughly similar doses and durations of treatment. We used RevMan 5 to analyse data for binary outcomes.

MAIN RESULTS

We identified 21 eligible studies: four (578 participants) evaluated the combination of an opioid with gabapentin or pregabalin; two (77 participants) evaluated an opioid with a tricyclic antidepressant; one (56 participants) of gabapentin and nortriptyline; one (120 participants) of gabapentin and alpha-lipoic acid, three (90 participants) of fluphenazine with a tricyclic antidepressant; three (90 participants) of an N-methyl-D-aspartate (NMDA) blocker with an agent from a different drug class; five (604 participants) of various topical medications; one (313 participants) of tramadol with acetaminophen; and another one (44 participants) of a cholecystokinin blocker (L-365,260) with morphine. The majority of combinations evaluated to date involve drugs, each of which share some element of central nervous system (CNS) depression (e.g. sedation, cognitive dysfunction). This aspect of side effect overlap between the combined agents was often reflected in similar or higher dropout rates for the combination and may thus substantially limit the utility of such drug combinations. Meta-analysis was possible for only one comparison of only one combination, i.e. gabapentin + opioid versus gabapentin alone. This meta-analysis involving 386 participants from two studies demonstrated modest, yet statistically significant, superiority of a gabapentin + opioid combination over gabapentin alone. However, this combination also produced significantly more frequent side effect-related trial dropouts compared to gabapentin alone.

AUTHORS' CONCLUSIONS

Multiple, good-quality studies demonstrate superior efficacy of two-drug combinations. However, the number of available studies for any one specific combination, as well as other study factors (e.g. limited trial size and duration), preclude the recommendation of any one specific drug combination for neuropathic pain. Demonstration of combination benefits by several studies together with reports of widespread clinical polypharmacy for neuropathic pain surely provide a rationale for additional future rigorous evaluations. In order to properly identify specific drug combinations which provide superior efficacy and/or safety, we recommend that future neuropathic pain studies of two-drug combinations include comparisons with placebo and both single-agent components. Given the apparent adverse impact of combining agents with similar adverse effect profiles (e.g. CNS depression), the anticipated development and availability of non-sedating neuropathic pain agents could lead to the identification of more favourable analgesic drug combinations in which side effects are not compounded.

Pharmacological versus microvascular decompression approaches for the treatment of trigeminal neuralgia: clinical outcomes and direct costs

In idiopathic trigeminal neuralgia (TN) the neuroimaging evaluation is usually normal, but in some cases a vascular compression of trigeminal nerve root is present. Although the latter condition may be referred to surgery, drug therapy is usually the first approach to control pain. This study compared the clinical outcome and direct costs of (1) a traditional treatment (carbamazepine [CBZ] in monotherapy [CBZ protocol]), (2) the association of gabapentin (GBP) and analgesic block of trigger-points with ropivacaine (ROP) (GBP+ROP protocol), and (3) a common TN surgery, microvascular decompression of the trigeminal nerve (MVD protocol). Sixty-two TN patients were randomly treated during 4 weeks (CBZ [n = 23] and GBP+ROP [n = 17] protocols) from cases of idiopathic TN, or selected for MVD surgery (n = 22) due to intractable pain. Direct medical cost estimates were determined by the price of drugs in 2008 and the hospital costs. Pain was evaluated using the Numerical Rating Scale (NRS) and number of pain crises; the Hospital Anxiety and Depression Scale, Sickness Impact Profile, and satisfaction with treatment and hospital team were evaluated. Assessments were performed at day 0 and 6 months after the beginning of treatment. All protocols showed a clinical improvement of pain control at month 6. The GBP+ROP protocol was the least expensive treatment, whereas surgery was the most expensive. With time, however, GBP+ROP tended to be the most and MVD the least expensive. No sequelae resulted in any patient after drug therapies, while after MDV surgery several patients showed important side effects. Data reinforce that, (1) TN patients should be carefully evaluated before choosing therapy for pain control, (2) different pharmacological approaches are available to initiate pain control at low costs, and (3) criteria for surgical interventions should be clearly defined due to important side effects, with the initial higher costs being strongly reduced with time.

Treatment options in trigeminal neuralgia

The incidence of trigeminal neuralgia (TN) is 4.3 per 100,000 persons per year, with a slightly higher incidence for women (5.9/100,000) compared with men (3.4/100,000). There is a lack of certainty regarding the aetiology and pathophysiology of TN. The treatment of TN can be very challenging despite the numerous options patients and physicians can choose from. This multitude of treatment options poses the question as to which treatment fits which patient best. The preferred medical treatment for TN consists of anticonvulsant drugs, muscle relaxants and neuroleptic agents. Large-scale placebo-controlled clinical trials are scarce. For patients refractory to medical therapy, Gasserian ganglion percutaneous techniques, gamma knife surgery and microvascular decompression are the most promising invasive treatment options.

Diagnosis and management of trigeminal neuropathic pains

SUMMARY Trigeminal neuropathic pains have presented diagnostic and therapeutic challenges to providers. In addition, knowledge of pathophysiology, current classification systems, taxonomy and phenotyping of these conditions are incomplete. While trigeminal neuralgia is the most identifiable and studied, other conditions are being recognized and require distinct management approaches. Furthermore, other facial pain conditions such as atypical odontalgia and burning mouth syndrome are now considered to have neuropathic elements in their etiology. This article reviews current knowledge on the pathophysiology, diagnosis and management of neuropathic pain conditions involving the trigeminal nerve, to include: trigeminal neuralgia, trigeminal neuropathic pain (with traumatically induced neuralgia and atypical odontalgia) and burning mouth syndrome. Treatment modalities are reviewed based on current and best available evidence. Trigeminal neuralgia is managed with anticonvulsant drugs as the first line, with surgical options providing variable results. Trigeminal neuropathic pain is managed medically based on the guidelines for other neuropathic pain conditions. Burning mouth syndrome is also treated with a number of neuropathic medications, both topical and systemic. In all these conditions, patients need to be thoroughly educated about their condition, involved in its management, and be provided with supportive and adjunctive treatment resources.

Trigeminal Neuralgia - A Debilitating Facial Pain

Trigeminal neuralgia (TN) is characterised by sudden usually unilateral severe, brief, stabbing, recurrent episodes of pain in the distribution of one or more branches of the trigeminal nerve.Diagnosis is largely based on clinical history due to the current lack of objective investigations.MRI can identify those patients who have TN secondary to an underlying pathology such as multiple sclerosis.The first line medical management remains carbamazepine, with oxcarbazepine being the second choice medication.Both percutaneous techniques targeting the Gasserian ganglion and microvascular decompression can be considered effective in the management of TN. Microvascular decompression is considered to provide on average, the longest pain free period post surgery.There are a number of TN associations and support groups which provide a valued service to patients and clinicians.Due to a dearth of high quality studies in many aspects of the condition, TN requires further research to be conducted.

Non-antiepileptic drugs for trigeminal neuralgia

BACKGROUND

Non-antiepileptic drugs have been used in the management of trigeminal neuralgia since the 1970s.

OBJECTIVES

The objective was to systematically review the efficacy and tolerability of non-antiepileptic drugs for trigeminal neuralgia.

SEARCH STRATEGY

For this updated review we searched the Cochrane Neuromuscular Disease Group Specialized Register (30 April 2010). We also searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), MEDLINE (January 1966 to April 2010), EMBASE (January 1980 to April 2010), LILACS (January 1982 to April 2010) and the Chinese Biomedical Retrieval System (1978 to April 2010). We handsearched 10 Chinese journals.

SELECTION CRITERIA

We searched for double-blind randomized or quasi-randomized controlled trials in which the active drug was used for at least two weeks.

DATA COLLECTION AND ANALYSIS

Two authors decided which trials fitted the inclusion criteria and independently graded risk of bias.

MAIN RESULTS

Four trials involving 139 participants were included. The primary outcome measure in each was pain relief. Three trials with an unclear risk of bias compared one of the non-antiepileptic drugs tizanidine, tocainide or pimozide with carbamazepine. In a trial of tizanidine involving 12 participants (one dropped out due to unrelated disease) one of five treated with tizanidine and four of six treated with carbamazepine improved, risk ratio 0.30 (95% CI 0.05 to 1.89). Few side effects were noted with tizanidine. In a study involving 12 participants there was an improvement in mean pain scores with tocainide similar to that with carbamazepine, but significant side effects limited its use. In the pimozide study more participants improved on pimozide (48/48) than with carbamazepine (27/48) (risk ratio 1.76, 95% CI 1.37 to 2.26). Up to 83% of participants reported adverse effects but these did not lead to withdrawal from the study. A trial with low risk of bias involving 47 participants compared 0.5% proparacaine hydrochloride eyedrops with placebo but did not show any significant benefits or side effects.

AUTHORS' CONCLUSIONS

Of the four studies identified, one had low and three an unclear risk of bias. There is insufficient evidence from randomized controlled trials to show significant benefit from non-antiepileptic drugs in trigeminal neuralgia. More research is needed.

Altered thermal sensitivity in neurons injured by infraorbital nerve lesion

Nerve lesions are common injuries. While peripheral sensitivity is lost, the partially regenerating nerve undergoes a complex transformation, occasionally leading to persistent pain syndromes. Changes of thermal perception following nerve injury have received little attention. This study investigates the sensitivity of trigeminal neurons after infraorbital nerve lesion in guinea-pigs. Cultured trigeminal neurons innervating the area of denervation were identified by retrograde transport of DiI deposited at the site of the lesion. The standardized protocol consisted of cold and heat stimulation starting from body temperature as well as application of menthol and capsaicin, while activation was quantified by Fura-2-based calcium microfluorimetry. Compared to neurons from control animals, DiI-positive neurons were similar in the percentage and extend of the responses to menthol and capsaicin. However, DiI-positive neurons were less responsive to cold stimulation and had a lower cold threshold when compared to DiI-negative or control neurons. At the same time, DiI-positive neurons were more responsive to heat stimulation and had a lower heat threshold compared to control neurons. In summary, the percentage of trigeminal neurons responsive to thermal or chemical stimulation did not change after axotomy. However, thermal sensitivity of these neurons was altered.

Effectiveness of the association between carbamazepine and peripheral analgesic block with ropivacaine for the treatment of trigeminal neuralgia

Treatment of trigeminal neuralgia (TN) is achieved by using adjuvant analgesics like antiepileptics, with carbamazepine (CBZ) being the first-line approach for TN patients, although side effects may be present. Other approaches using gabapentin, namely when associated with peripheral analgesic block of TN trigger points with the local anesthetic ropivacaine (ROP), resulted in decreased pain and daily drug intake (reduced side effects). This study evaluates if the association between CBZ and the peripheral block with ROP reinforces the clinical value of CBZ. In this parallel, double-blinded study, idiopathic TN patients were randomized to receive during 4 weeks either CBZ (CBZ; n = 21) or CBZ associated with the peripheral analgesic block using ROP (CBZ + ROP; n = 24). The primary outcome measures were the following: i) pain intensity, evaluated by the numerical rating scale; ii) number of pain crises; and iii) number needed to treat. Evaluation points were at the beginning (day 1) and end (day 29) of treatment and after a follow-up of 5 months (month 6). Both protocols resulted in a decrease of pain intensity and number of pain crises, but only the association CBZ + ROP showed i) a significant stronger reduction in pain intensity at month 6 and ii) a significant decrease in the daily dose of CBZ given to patients (both at day 29 and month 6). In contrast, the daily dose in CBZ-only patients remained constant or even increased. The number needed to treat for the association CBZ + ROP over the CBZ protocol reduced from 5 at the end of the 4-week treatment to 3 after the 5-month follow-up. Data reinforce the use of CBZ as a primary tool to control pain in TN patients, as the association CBZ + ROP i) improves the clinical qualities of CBZ, ii) strongly reduces the daily dose of CBZ, and iii) reduces the potential side effects attributed to high doses of CBZ.

Medical management of trigeminal neuropathic pains

IMPORTANCE OF THE FIELD

Although trigeminal neuralgia has traditionally been considered the prime neuralgic condition in the face region, other forms of neuropathic pain are now being more frequently recognized and require recognition and a different management approach.

AREAS COVERED IN THIS REVIEW

This review principally covers medical management of trigeminal neuralgia; but also included is glossopharyngeal neuralgia, trigeminal neuropathic pain (atypical odontalgia) and burning mouth syndrome. Systematic reviews and guidelines will be discussed.

WHAT THE READER WILL GAIN

An update will be provided of drug therapy for these relatively rare facial pains.

TAKE HOME MESSAGE

Trigeminal neuralgia continues to be best managed using anticonvulsant drugs, the primary ones being carbamazepine and oxcarbazepine; baclofen may be helpful and, of the newly emerging drugs, pregabalin has potential. Glossopharyngeal neuralgia remains managed in the same way as trigeminal neuralgia. Trigeminal neuropathic pain is probably best managed according to guidelines used for the management of neuropathic pain, which include the use of tricyclic antidepressants, gabapentin, pregabalin, duloxetine, venalafaxine and topical lidocaine. Burning mouth syndrome is a neuropathic pain managed initially with topical clonazepam and then with other neuropathic drugs. Patients need to be involved in their management.

EFNS guidelines on the pharmacological treatment of neuropathic pain: 2010 revision

BACKGROUND AND OBJECTIVES

This second European Federation of Neurological Societies Task Force aimed at updating the existing evidence about the pharmacological treatment of neuropathic pain since 2005.

METHODS

Studies were identified using the Cochrane Database and Medline. Trials were classified according to the aetiological condition. All class I and II randomized controlled trials (RCTs) were assessed; lower class studies were considered only in conditions that had no top-level studies. Treatments administered using repeated or single administrations were considered, provided they are feasible in an outpatient setting.

RESULTS

Most large RCTs included patients with diabetic polyneuropathies and post-herpetic neuralgia, while an increasing number of smaller studies explored other conditions. Drugs generally have similar efficacy in various conditions, except in trigeminal neuralgia, chronic radiculopathy and HIV neuropathy, with level A evidence in support of tricyclic antidepressants (TCA), pregabalin, gabapentin, tramadol and opioids (in various conditions), duloxetine, venlafaxine, topical lidocaine and capsaicin patches (in restricted conditions). Combination therapy appears useful for TCA-gabapentin and gabapentin-opioids (level A).

CONCLUSIONS

There are still too few large-scale comparative studies. For future trials, we recommend to assess comorbidities, quality of life, symptoms and signs with standardized tools and attempt to better define responder profiles to specific drug treatments.

[Bilateral trigeminal neuralgia: case report]

BACKGROUND AND OBJECTIVES

Trigeminal neuralgia is an extremely painful condition characterized by recurrent episodes of sudden, lancinating, shock-like pain lasting from a few seconds to two minutes usually unilateral. It has an annual incidence of approximately 4.3 in 100,000 in the general population and only 3% of those cases present bilateral manifestation. The objective of this report was to describe a rare case of bilateral trigeminal neuralgia.

CASE REPORT

A 61 years old housewife from Maranhão, Brazil, married, with a history of hypertension, presented with a six-year history of severe pain in the left V2-V3 regions, lasting 5 to 10 seconds, in the lateral aspect of the nose and mandible, worsening by talking, chewing, and with a decrease in temperature. She had been treated with chlorpromazine (3 mg every eight hours) and carbamazepine (200 mg every eight hours) during six months without improvement. On physical exam, the patient presented thermal and mechanical allodynia in the V2-V3 regions. She was using gabapentin (1,200 mg/day) with partial relief of the pain. The dose of gabapentin was increased to 1,500 mg/day and amitriptyline 12.5 mg at night was added to the therapeutic regimen. The patient evolved with mild and sporadical pain and a reduction in pain severity during 10 months; the dose of gabapentin was progressively reduced to 600 mg/day, and amitriptyline was maintained at 12.5 mg/day. After one year, the patient developed similar pain in the region of the right mandible, which improved with an increase in the dose of gabapentin to 900 mg/day. Head CT and MRI did not show any abnormalities.

CONCLUSIONS

Carbamazepine is the first choice for the treatment of trigeminal neuralgia; however, the use of gabapentin as the first pharmacological choice or in cases refractory to conventional therapy has been increasing.

Update on trigeminal neuralgia

Trigeminal neuralgia leads to paroxysms of short-lasting but very severe pain. Between attacks, patients are usually asymptomatic, but a constant dull background pain may persist in some cases. The incidence of trigeminal neuralgia is 4.3 per 100,000 persons per year, with a slightly higher incidence for women (5.9 per 100,000) compared with men (3.4 per 100,000). There is a lack of certainty regarding the etiology and pathophysiology of trigeminal neuralgia. There are a wide range of medical and surgical treatments available. The preferred medical treatment for trigeminal neuralgia consists of anticonvulsant drugs, muscle relaxants and neuroleptic agents. Large-scaled placebo-controlled clinical trials are scarce. For patients refractory to medical therapy, Gasserian ganglion percutaneous techniques, gamma-knife surgery and microvascular decompression are the most promising invasive treatment options. Continuous scientific research works towards a better understanding of trigeminal neuralgia and has accomplished a greater insight into the underlying pathophysiological mechanisms.