To date, in the largest series of patients treated with lacosamide after first-line treatment failure, pain relief was achieved in 66% of patients, with a relatively low proportion of mild adverse events.
Recently published data from a retrospective descriptive cohort study suggest that treatment with oral lacosamide can be a valid alternative for patients with trigeminal neuralgia (TN) who fail first-line treatments, apart from its potential previously reported use as an intravenous rescue medication.
Published in Headache, data were collected on 86 patients with refractory TN who attended a tertiary center between 2015 and 2021. After failing a previous first-line treatment, patients received lacosamide, with dose determined by the attending neurologist based on clinical criteria and patient comorbidities. The median time since TN diagnosis was 4.6 years, and TN etiology was secondary in 19% (n = 16) of the cases.
Led by Albert Munoz-Vendrell, MD, neurologist, Hospital Universitari de Bellvitge, all patients included in the study had previously tried carbamazepine or oxcarbazepine, 2 commonly used therapies to treat TN. More than half (54%) of the cohort continued on either of those therapies as a concomitant treatment, and 14% were treated with lacosamide as monotherapy. The median initial daily lacosamide dose was 100 mg (range, 50-400), and the median maintenance daily dose was 200 mg (range, 50-600).
At the conclusion of the analysis, two-thirds (66%) of patients achieved pain relief from their condition. Adverse events (AEs), found in 33% of the cohort, were mild in all cases. Absence of pain, a secondary end point, was achieved by 34% (n = 29) of the sample. During the follow-up, 44% (n = 38) of patients suspended lacosamide treatment, with reasons that included clinical improvement (34%; n = 13), inefficacy (45%; n = 17), and intolerance (21%; n = 8). Investigators found no statistically significant differences in demographical and clinical data between responders and nonresponders, except for bilateral pain distribution, for which the 3 patients were all nonresponders.
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When comparing those with (54%) and without (46%) concomitant use of carbamazepine or oxcarbazepine, findings showed no significant differences in the proportion of patients who achieved pain relief (67% vs 65%; P = .824) or in AEs (35% vs 30%; P = .653). The investigators noted that these findings add to the uncertainty of whether to use lacosamide as an alternative treatment to carbamazepine or as an add-on therapy. "Further prospective studies are needed to draw clearer conclusions and better control for covariates, such as dose adjustments and reasons for treatment change."
Although nonsignificant differences were observed between responders and nonresponders, investigators noted some predictors that should be considered when assessing the TN characteristics of each arm. First, a major proportion of secondary TN was observed in nonresponders (24% vs 16%; P = .387), which was consistent from previous reports suggesting a lower treatment response in this group of patients.2
The study also showed that the presence of concomitant continuous pain seemed to be more prevalent on nonresponders (41% vs 28%; P = .232), which was in line with previously reported low response to medical and surgical treatment of this group of patients. Lastly, a major proportion of patients with evident neurovascular contact producing morphologic changes on the MRI were observed in the responder arm (23% vs 10%; P = .242), while none of the 3 cases of bilateral pain distribution responded to the treatment.
"These data pave the way to identifying the optimal patient profile for lacosamide use, which is likely to be a patient with classic TN and unilateral pure paroxysmal pain,” Munoz-Vendrell et al wrote.