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Título

ONABOTULINUM TOXIN TYPE A AS AN ADD-ON THERAPY IN REFRACTORY TRIGEMINAL NEURALGIA: PRELIMINARY RESULTS

RESUMO

Introduction: Trigeminal neuralgia (TN) is a rare but often debilitating condition, characterized by paroxysmal attacks of sharp pain in one or more branches of the trigeminal nerve. Although several pharmacological options are available for prophylaxis, the treatment of TN is frequently unsatisfactory. Onabotulinum toxin type A (OBTA) is proven safe and effective in migraine and cranial neuralgias such as occipital neuralgia, representing a possible therapeutic option in TN. Objectives: This study evaluated the effects of OBTA injections in a cohort of patients with refractory TN. Methods: We enrolled patients with confirmed TN referred to our botulinum toxin outpatient clinic, taking standard oral prophylaxis with partial or no response. The Intensity (estimated with the visual analog pain scale) and frequency of pain (estimated by the number of days with pain per month) were noted before the start of prophylaxis, with prophylaxis alone, and 3 months after OBTA injections. OBTA dosage and number of injection points, as well as other demographic and clinical data, were noted. Results: Our preliminary sample of 20 patients was marked by a predominance of females (n = 11, 55%), with a median age of 70.5 years (Min 44, Max 87), with idiopathic TN (n = 12, 60%). Carbamazepine was the most frequent prophylactic (used by 14 patients, 70% of the sample). Patients reported pain with a median intensity of 10 (Min 9, Max 10) and occurring daily (30 days with pain per month in the entire sample) before prophylaxis. Although prophylaxis was effective to reduce pain intensity, lowering an average of 3.5 points (p < 0.0001, IC 95% 2 – 5), it was ineffective to reduce the frequency, and the entire sample maintained daily pain. When compared to prophylaxis alone, OBTA + Prophylaxis further reduced intensity on average by 4.9 points (p < 0.0001, IC 95% 3 – 5.9), and reduced frequency on average by 28 days with pain per month (p = 0.002, IC 95% 23 – 30). In our sample, 7 patients (35% of the sample) reported a full response. The mean duration of effect was 80.75 ± 20.14 days. No side effects were registered in our sample. Conclusion: Our results suggest that OBTA is a safe and effective add-on treatment option for patients experiencing TN refractory to oral prophylaxis. Although OBTA was particularly effective in reducing the frequency of painful episodes, further studies are necessary to confirm these findings.

Palavras Chave

chronic pain; headache; trigeminal neuralgia; botulinum toxin