To Evaluate Efficacy of Monotherapy of Oxcarbazepine Versus Combination of Gabapentin With Oxcarbazepine in the Management of Trigeminal Neuralgia

To Evaluate Efficacy of Monotherapy of Oxcarbazepine Versus Combination of Gabapentin With Oxcarbazepine in the Management of Trigeminal Neuralgia.

ABSTRACT:

Objective: This study evaluates the effectiveness of oxcarbazepine monotherapy with the combination of gabapentin and oxcarbazepine in managing trigeminal neuralgia(TN).

Methods: A prospective observational study was conducted at Rehman College of Dentistry for the duration of one year, i.e., from 1st May 2023 till May 2024. A total of 44 patients, fulfilling inclusion criteria, were included.Half were given monotherapy with oxcarbazepine (300 mg twice daily) and half were given combination therapy with gabapentin (100 mg daily) plus oxcarbazepine. Pain was evaluated utilizing the Visual Analogue Scale (VAS) at baseline, 2 weeks, and 2 months. SPSS software version 26 was used for statistical analysis.

KEYWORDS: Combination Therapy, Gabapentin, Monotherapy, Oxcarbazepine, Trigeminal Neuralgia, Visual Analogue Scale.

Study Overview

• Status: Completed
• Conditions: Pain; Pain Management; Effectiveness of Drugs Was Compared for Treating Trigeminal Neuralgia
• Intervention / Treatment: Drug: oxcarbamezapine(300 mg twice daily); Drug: combination therapy(oxcarbamezapine 300 mg twice daily and gabapentine)

Detailed Description

INTRODUCTION:

Orofacial pain is defined as pain in and around the oral cavity. The orofacial region is complex, and any pain of orofacial origin could be related to the hard or soft tissue in that region or a dysfunction of the nervous system. Amongst all the orofacial pains, trigeminal neuralgia is one of the most debilitating, which badly affects the quality of life of the patient1. Trigeminal neuralgia is defined by the International Classification of Headache Disorders as abrupt, sharp, spontaneous pain that is caused by activation of one or more trigeminal nerve branches and lasts for a few seconds to two minutes. Classic trigeminal neuralgia (idiopathic) typically manifests at 40-60 years of age, whereas symptomatic trigeminal neuralgia (due to compression of the trigeminal ganglion) typically manifests around 30-40 years of age. There are two categories of treatment for trigeminal neuralgia: surgical and medicinal. But no single surgical or medicinal procedure has had a 100% success rate. Neuroleptic medications, muscle relaxants, and anticonvulsants are the recommended medical treatments for TN. However, the most popular invasive therapy choices for individuals not responding to conservative measures include gamma knife surgery, microvascular decompression, and gasserian ganglion percutaneous procedures3. Carbamazepine is generally regarded as the first-line medication for the treatment of trigeminal neuralgia among the recommended medical interventions. But not every patient can take carbamazepine, which might make compliance difficult. Moreover, liver failure, aplastic anemia, and hyponatremia are significant side effects of carbamazepine. The structural analogue of carbamazepine is oxcarbazepine. Oxcarbazepine is more well-tolerated in patients than carbamazepine because it selectively induces P450 enzymes, has fewer pharmacologic interactions with other drugs, and has fewer adverse effects. Gabapentin is an analogue of GABA and is useful for the treatment of neuropathic pain. Second-line drugs like gabapentin are added if the patient is unable to tolerate the adverse effects or drug interactions4. Trigeminal neuralgia is a severely incapacitating illness that affects fundamental human activities, including eating, drinking, talking, and touching one's face. As a result, it interferes with day-to-day activities. According to epidemiological research, there is a higher risk of anxiety, depression, and suicide5. For accurate diagnosis and treatment, a thorough history and identification of the affected nerve are crucial. In Pakistan, many trigeminal neuralgia patients have incorrect diagnoses, lead to pointless operations, and receive inefficient therapies. The purpose of this study is to evaluate the efficacy of gabapentin combination regimens versus monotherapy (oxcarbazepine). The extant literature indicates that there has not yet been a single national or international trial that compares the efficacy of oxcarbazepinemonotherapy with combined therapy using gabapentin, though studies comparing other treatment options or medicines have been conducted 6,7.

METHODS:

Prospective observational study was conducted at Rehman College of Dentistry for the duration of one year, i.e., from 1st May 2023 till May 2024. Universal sampling was used, and 44 patients who reported to our dental OPD and fulfilled the inclusion criteria were included in the study. Patients of either gender, with ages ranging from 20 to 80 years, presenting in the Outpatient Department, who fulfilled the diagnostic criteria of idiopathic trigeminal neuralgia according to the International Headache Society, were included in the study. All patients with orofacial and odontogenic pain other than TN, TMJ disorders having a centralized cause of TN as evidenced by MRI, patients unwilling to participate or who failed to show up for follow-up, pregnant and lactating females, patients who had previous surgical procedures for neuralgia or are allergic to neuralgia medications, and patients with comorbid conditions were excluded from the study. After seeking ethical approval from the Institutional Research Board (via reference number RCD-04-23-167), written consent was taken, and patients were randomly assigned to one of the two groups through block randomization using the lottery method. Patients randomly distributed into two groups were given monotherapy with oxcarbazepine or combination therapy with gabapentin in addition to oxcarbazepine. Pain was calculated on a Visual Analogue Scale (0-10). Pain variable would again be calculated at 2 weeks and 2 months. Data analysis was conducted using the SPSS program 26. Qualitative data were displayed as frequency and percentage, whereas quantitative variables were displayed as mean ± SD. The independent sample t-test was used to compare the mean pain score between the groups; a p-value of less than 0.05 was deemed significant.

• Study Type: Interventional
• Enrollment (Actual): 44
• Phase: Phase 2; Phase 3

Contacts and Locations

Study Locations

• Pakistan
  • Khyber Pakhtunkhwa
    • Peshawar, Khyber Pakhtunkhwa, Pakistan, 25100
      • Rehman College of Dentistry

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients of either gender aged 20-80 years
• Patients presenting to the Outpatient Department (OPD)
• Patients fulfilling the diagnostic criteria for idiopathic trigeminal neuralgia according to the International Headache Society (IHS)

Exclusion Criteria:

• Patients with orofacial or odontogenic pain conditions other than trigeminal neuralgia (TN)
• Patients with temporomandibular joint (TMJ) disorders
• Patients with a centralized cause of TN evident on MRI
• Patients unwilling to participate in the study
• Patients who failed to attend follow-up visits
• Pregnant or lactating females
• Patients with a history of previous surgical procedures for neuralgia
• Patients with known allergy to medications used for neuralgia
• Patients with significant comorbid medical conditions

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Oxcarbamezapine monotherapy; group given monotherapy with oxcarbamezapine	Drug: oxcarbamezapine(300 mg twice daily); monotherapy with oxcarbamezapine(300 mg twice daily)
Active Comparator: Oxcarbamezapine plus gabapentine combination therapy; group given comination therapy(oxcarbamezapine with gabapentine)	Drug: combination therapy(oxcarbamezapine 300 mg twice daily and gabapentine); combination therapy of oxcarbamezapine with gabapentine was given

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Pain Intensity Scores Assessed by Visual Analog Scale (VAS)	Pain intensity was assessed using the Visual Analogue Scale , a 10-cm horizontal line ranging from 0 to 10, where 0 represents no pain and 10 represents the worst imaginable pain. Higher scores indicate greater pain severity (worse outcome). Participants will receive either oxcarbazepine monotherapy or combination therapy with gabapentin plus oxcarbazepine. VAS pain scores will be recorded at baseline, 2 weeks, and 2 months to evaluate changes in pain intensity over time.	Baseline, 2 weeks, and 2 months after initiation of treatment

Collaborators and Investigators

• Sponsor: Rehman Medical Institute - RMI
• Investigators: Study Director: iftikhar qayum, MBBS, MD, PHD, Rehman Medical Institute

Publications and helpful links

General Publications

• Lee JY, Lee GH, Yi SH, Sim WS, Kim BW, Park HJ. Non-Surgical Treatments of Trigeminal Neuralgia from the Perspective of a Pain Physician: A Narrative Review. Biomedicines. 2023 Aug 21;11(8):2315. doi: 10.3390/biomedicines11082315.
• Cheshire WP Jr. Defining the role for gabapentin in the treatment of trigeminal neuralgia: a retrospective study. J Pain. 2002 Apr;3(2):137-42. doi: 10.1054/jpai.2002.122944.
• Texakalidis P, Xenos D, Tora MS, Wetzel JS, Boulis NM. Comparative safety and efficacy of percutaneous approaches for the treatment of trigeminal neuralgia: A systematic review and meta-analysis. Clin Neurol Neurosurg. 2019 Jul;182:112-122. doi: 10.1016/j.clineuro.2019.05.011. Epub 2019 May 14.
• Das B, Saha SP. Trigeminal neuralgia: current concepts and management. J Indian Med Assoc. 2001 Dec;99(12):704-9.
• Ishikawa R, Iseki M. [Pharmacological Treatment of Trigeminal Neuralgia]. No Shinkei Geka. 2024 Jan;52(1):63-69. doi: 10.11477/mf.1436204880. Japanese.

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2023
• Primary Completion (Actual): May 1, 2024
• Study Completion (Actual): May 1, 2024

Study Registration Dates

• First Submitted: May 13, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 4, 2026

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Neurobehavioral Manifestations; Perceptual Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Agnosia; Amino Acids, Peptides, and Proteins; Organic Chemicals; Hydrocarbons; Cyclohexanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Acids, Acyclic; Carboxylic Acids; Amines; Amino Acids; gamma-Aminobutyric Acid; Aminobutyrates; Butyrates; Acids, Carbocyclic; Cyclohexanecarboxylic Acids; Gabapentin
• Other Study ID Numbers: RCD-04-23-167; Ethical approval RCD-04-23-167 (Other Identifier: rehman college of dentistry)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Relevant data can be shared upon genuine request
• IPD Sharing Time Frame: Available indefinitely
• IPD Sharing Access Criteria: Other researchers doing similar drug trials. Access will be through email requests.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; CSR

Study Data/Documents

1. Study Protocol
   Information identifier: journal of RMI
   Information comments: Article will be published in JRMI

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No