Eslicarbazepine acetate, an alternative for patients with trigeminal neuralgia with hyponatremia induced by carbamazepine or oxcarbazepine
Year: 2024
Type: article
Abstract: Dear Editor, I read with interest the article by Ansari MZ et al.,[1] in which they presented a case of aggravation of trigeminal neuralgia (TN) induced by hyponatremia in a patient being treated with oxcarbazepine (OXC), and I would like to make some contributions that might be of use in our clinical practice. Voltage-gated sodium channel (Nav) blockers, specifically the subclass of carboxamides, include carbamazepine (CBZ), OXC and, more recently, eslicarbazepine acetate (ESL). Hyponatremia, defined as a level of sodium <135 mEq/L, is a common side effect of treatment with CBZ and OXC, whose incidence ranges between 4.8% and 40%, according to the literature consulted. A growing number of works provide data for hyponatremia, even when mild, having harmful effects, above all among the elderly population (in which, furthermore, symptoms of neuropathic pain frequently occur). Hyponatremia with pharmacological origins should be regarded as an adverse effect to be taken into account and that justifies considering a change of treatment.[2] CBZ and OXC are the first line of medical treatment in TN, and lamotrigine, baclofen, pregabalin or gabapentin may be added to CBZ/OXC when they fail.[3] ESL can be considered as an alternative for patients who display side effects of CBZ. In the clinical trials and observational studies published with ESL on epilepsy, hyponatremia is practically nonexistent and so replacing CBZ and OXC with ESL in patients who developed hyponatremia appears to be an effective and well-tolerated option. Nevertheless, monitoring hyponatremia is recommended, as in some patients the drop in sodium levels in the blood persists. However, there is barely any evidence to recommend the use of ESL in TN. The majority of literature available is from open observational studies with no control group and a small number of patients.[4] Although a retrospective, open-label, multicentric, intention-to-treat study supports the hypothesis that ESL is an effective, safe and well-tolerated treatment for the treatment of TN. Eighteen patients were included. After the treatment with ESL, the median of pain intensity improved from 9.5 to 2.5 (P < 0.001) and the median of pain paroxysms frequency improved from 70 episodes per week to 0.37 (P < 0.001). Reply rate was 88.9% and 44.4% became asymptomatic after treatment. Sixty-one per cent of patients presented some adverse event. Despite this, 16 patients (88.9%) noted a good subjective tolerance to ESL.[5] The differences in pharmacological profile of these pharmaceuticals may be associated with changes relating to effectiveness, tolerability and adherence.[2] In clinical practice, all of this leads to consideration being given to swapping one of these drugs for another from this family in order to adapt to the patient profile as best as possible. The EPICON Project, undertaken by a group of epilepsy experts in Spain using the Delphi method, assessed certain situations and methods to switch from CBZ and OXC to ESL. The aim of the study was to attempt to establish a consensus of recommendations that could be considered in order to adequately switch from CBZ or OXC to ESL in certain patients. The key recommendations were the switch from CBZ to ESL must be carried out over a period of 1–3 weeks, with a CBZ: ESL dose equivalence of 1:1.3, and it is recommended in patients who forget their medication, those who do shift work, polymedicated patients, or those with cognitive problems, severe osteoporosis-osteopenia, dyslipidemia or liver disease (other than acute liver failure), and also in men with erectile dysfunction caused by CBZ. The switch from OXC to ESL can be done from one day to the next with a 1:1 dose equivalence and it is recommended for patients who forget their medication, who do shift work, polymedicated patients or those with cognitive problems. The switch is not recommended for patients with a rash due to CBZ or OXC.[6] Although these recommendations are given for patients with epilepsy, we can use them as a guide in other circumstances (different models of neuropathic pain, TN and other headaches) where patients show the described problems relating to adherence/tolerability with CBZ and OXC. Therefore, I strongly recommend further research and clinical trials to evaluate the efficacy and safety of ESL in TN more robustly and I suggest specific areas of study, such as randomized controlled trials, long-term safety assessments, and patient-reported outcomes. List of abbreviations TN = Trigeminal neuralgia OXC = Oxcarbazepine CBZ = Carbamazepine ESL = Eslicarbazepine acetate. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Author: Antonio Alcántara Montero
Language: English
Subfield: Pathology and Forensic Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $450
OpenAlex ID: W4404432918