Discontinuation of Peripheral Nerve Blocks and OnabotulinumtoxinA From Adverse Effects in Chronic Migraine
A retrospective cohort study observed no significant difference in the number of patients who discontinued concurrent peripheral nerve blocks and onabotulinumtoxinA, which the authors recognized as a marker of clinical relevance.
Christopher C. Anderson, MD
In a recent retrospective cohort study, patients who received both onabotulinumtoxinA (Botox; Allergan) and nerve blocks showed a statistically significant difference in the number of adverse events (AEs) leading to discontinuation of therapy in comparison with individuals on onabotulinumtoxinA alone. These results provide evidence of the subsequent administration of local anesthetic and onabotulinumtoxinA for the treatment of migraine during a single clinical encounter, and adds to the current lack of safety data.1
Although there was a significant difference in the number of AEs in patients on the combination therapy that led to discontinuation of therapy (0.8% [1/131] vs 4.6% [6/131], P = .065), the analysis showed no significant difference in total AEs between combination therapy compared to nerve blocks alone or onabotulinumtoxinA alone. Notably, the authors observed 1 patient out of the whole cohort (0.8%) that accounted for 67%, or 4 out of 6 AEs in the combination group.
"We felt that this patient's report likely limited the use of this measure (absolute number of adverse events that led to discontinuation) as an accurate representation of patient experience. As a result, sequential administration of peripheral nerve blocks and onabotulinumtoxinA does not appear to generate a statistically significant risk of overall adverse events compared to the individual procedures of only peripheral nerve blocks or only onabotulinumtoxinA," coauthor Christopher C. Anderson, MD, headache medicine fellow physician at Mayo Clinic, and colleagues wrote.1
Presented at the 2023 American Headache Society (AHS) Annual Meeting, June 15-18, in Austin, Texas, the objective of the study was to explore the safety and tolerability of concurrent peripheral nerve blockade and onabotulinumtoxinA treatment during a single outpatient clinic visit. Anderson and colleagues hypothesized that the combined procedure would be a safe and well-tolerated therapy for patients with chronic migraine and other headache disorders.
Investigators used clinical data from 1 outpatient headache clinic over a 16-month time period to conduct the retrospective review. Adult patients with migraine were recruited by procedure codes and deemed eligible if they received peripheral nerve block(s) and onabotulinumtoxinA injections during a single encounter in the study period for their treatment of chronic migraine. Patients were ineligible if they were under the age of 18 years, received their treatment outside of the clinic, or were given sphenopalatine ganglion blocks. The controls for the study were age- and sex-matched patients that received either peripheral nerve block or onabotulinumtoxinA.
In this safety study, the primary outcome was a comparison of the number of AEs experienced in individuals on the combination of the therapies compared with those who were in the single intervention control arm. The data on the AEs were collected through a review of progress notes, procedure notes, and participant portal messages. If there was a record of an AE, it was graded by a reviewer using the Common Terminology Criteria for Adverse Events which ranged from grade 1 mild event to grade 5 death. It was also noted whether the AE led the participant to discontinue using the treatment.
Among the total of 375 patients enrolled, 132 had combination treatments with peripheral nerve block(s) and onabotulinumtoxinA. In addition, 137 patients treated on onabotulinumtoxinA alone and 106 treatments with peripheral nerve block(s) alone were included. After conducting the age- and sex-matching of controls, 131 patients who received the combination therapy were compared with 131 patients who received onabotulinumtoxinA alone. Also, 104 patients who received combination therapy were compared with 104 patients that received peripheral nerve block(s) alone.
"Procedural options for headache treatment serve to supplement standard methods, which typically include daily, oral medications or – more recently – monthly subcutaneous injectable agents," coauthor Christopher C. Anderson, MD, headache medicine fellow physician at Mayo Clinic, and colleagues wrote.1 "Because of the frequent cooccurrence of cranial neuralgia and chronic migraine, greater occipital nerve blocks can be used as adjunct therapy in chronic migraine patients receiving onabotulinumtoxinA in routine clinical practice and may ease the burden of multiple oral therapies and provide an additional route of treatment when further oral medications are contraindicated because of medical comorbidities or otherwise intolerable due to adverse events."
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