Comparing intravenous lacosamide with intravenous phenytoin for severe flare-ups of trigeminal neuralgia
| ISRCTN | ISRCTN92009764 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN92009764 |
| Protocol number | 112/25 |
| Sponsor | Instituto Nacional de Neurología y Neurocirugía |
| Funder | National Institute of Neurological Disorders and Stroke |
- Submission date
- 22/07/2026
- Registration date
- 22/07/2026
- Last edited
- 22/07/2026
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nervous System Diseases
Prospectively registered
Protocol
Statistical analysis plan
Results
Individual participant data
Record updated in last year
Plain English summary of protocol
Not provided at time of registration
Contact information
Dr Javier Andres Galnares-Olalde
Principal investigator, Scientific, Public
Principal investigator, Scientific, Public
Av. Insurgentes Sur 3877, La Fama, Tlalpan
Mexico City
14269
Mexico
 ORCID ID |
0000-0003-3004-6221 |
|---|---|
| Phone | +52 55 5606 3822 |
| javiergalnares.neurologia@gmail.com |
Study information
| Primary study design | Interventional |
|---|---|
| Allocation | Randomized controlled trial |
| Masking | Open (masking not used) |
| Control | Active |
| Assignment | Parallel |
| Purpose | Treatment |
| Scientific title | A randomized open-label pilot trial comparing intravenous lacosamide with intravenous phenytoin for pain reduction and adverse events in adults with acute exacerbations of trigeminal neuralgia |
| Study objectives | To compare the effectiveness and safety of intravenous lacosamide versus intravenous phenytoin in adults with acute exacerbations of trigeminal neuralgia. The primary objective was to compare the proportion of participants achieving at least a 50% reduction in pain intensity at 2 hours after infusion. Secondary objectives were to evaluate pain improvement over 24 hours, the need for additional medication, and treatment-related adverse events. |
| Ethics approval(s) |
Approved 01/12/2025, Research Ethics Committee of Manuel Velasco Suárez National Institute of Neurology and Neurosurgery, (Comité de Ética en Investigación, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez) (Avenida Insurgentes Sur 3877, Colonia La Fama, Alcaldía Tlalpan, Mexico City, 14269, Mexico; +52 55 5606 3822; comite.etica@innn.edu.mx), ref: CEI/218/2025 |
| Health condition(s) or problem(s) studied | Acute exacerbations of trigeminal neuralgia |
| Intervention | Participants were randomized in a 1:1 ratio to receive a single intravenous dose of lacosamide or phenytoin. The allocation sequence was implemented using sequentially numbered, sealed envelopes prepared in advance by an independent investigator. The study was open label. Participants allocated to the lacosamide group received lacosamide 200 mg intravenously, infused over a minimum of 15 minutes. Participants allocated to the phenytoin group received phenytoin 15 mg/kg intravenously at a maximum infusion rate of 50 mg/min. Before treatment, participants underwent clinical assessment, pain evaluation using a 0–10 numerical rating scale, vital-sign measurement, and electrocardiography. Participants were monitored during and after the infusion. Pain intensity, additional medication requirements, and adverse events were evaluated at 2, 6, 12, and 24 hours after treatment. The 6-, 12-, and 24-hour assessments were conducted using structured telephone follow-up after discharge when applicable. Total participant follow-up was 24 hours. |
| Intervention type | Drug |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | Lacosamide, phenytoin |
| Primary outcome measure(s) |
|
| Key secondary outcome measure(s) | |
| Completion date | 28/05/2026 |
Eligibility
| Participant type(s) | |
|---|---|
| Age group | Mixed |
| Lower age limit | 18 Years |
| Upper age limit | 100 Years |
| Sex | All |
| Target sample size at registration | 52 |
| Total final enrolment | 57 |
| Key inclusion criteria | 1. Adults aged 18 years or older 2. Diagnosis of classical, secondary, or idiopathic trigeminal neuralgia according to the International Classification of Headache Disorders, third edition (ICHD-3) 3. Acute exacerbation, defined as a sudden increase in pain frequency or intensity that is not controlled with the participant’s usual oral treatment 4. Requirement for intravenous treatment in a hospital or emergency department setting 5. Written informed consent |
| Key exclusion criteria | 1. Known hypersensitivity to lacosamide or phenytoin 2. Use of lacosamide during the previous two weeks 3. Clinically relevant cardiac arrhythmia, particularly uncontrolled second- or third-degree atrioventricular block 4. Severe hepatic impairment 5. Severe renal impairment 6. Pregnancy or breastfeeding 7. Active epileptic seizures |
| Date of first enrolment | 01/12/2025 |
| Date of final enrolment | 27/05/2026 |
Locations
Countries of recruitment
- Mexico
Study participating centres
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|
Editorial Notes
22/07/2026: Study’s existence confirmed by the Research Ethics Committee of Manuel Velasco Suárez National Institute of Neurology and Neurosurgery, (Comité de Ética en Investigación, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez), Mexico.
