Study Finds GONB With Bupivacaine Inferior to IV Metoclopramide as First-line Treatment for Migraine

According to a study published in Headache, greater occipital nerve blocks (GONB) using bupivacaine were not as effective as intravenous (IV) metoclopramide as a first-line treatment for migraineurs who presented to emergency departments (ED).

Each year, more than 1 million individuals in the United States present to EDs for acute treatment of migraine, but less than 25% of patients with migraine in the ED achieve headache relief and remain headache free for 48 hours.

Recently, GONB have been used to treat acute migraine, and some data suggest that the blocks may provide rapid and sustained relief with minimal adverse effects. “This procedure is hypothesized to work by decreasing transmission through the trigeminocervical complex (TCC), an important way-station in migraine pathogenesis,” the authors wrote, although clinical evidence supporting the mechanism is limited.

To determine whether GONB using bupivacaine would alleviate pain as well as or better than IV metoclopramide, researchers conducted a randomized, double-dummy, clinical trial comparing the 2 treatments.

Eligible participants presented to 2 EDs of the Montefiore Medical Center in the Bronx, New York. All patients were 18 years or older and visited EDs for an acute headache of moderate or severe intensity meeting International Classification of Headache Disorders, 3rd edition criteria. Pregnant or lactating patients were excluded from the study, along with individuals who had previously been treated with GONB.

Patients were randomized 1:1 to either receive a total of 6 mL of bupivacaine 0.5%, injected adjacent to the greater occipital nerve bilaterally (3 mL each side), in addition to an intravenous drip containing normal saline placebo (administered over 15 minutes), or a sham GONB consisting of 6 mL of normal saline, injected adjacent to the greater occipital nerve bilaterally (3 mL each side), in addition to an intravenous drip containing 10 mg metoclopramide, also administered over 15 minutes.

All patients, clinicians, and research associates who assessed outcomes were blinded to the treatments administered. Over 2.5 years, 1358 patients were screened for participation while 99 were ultimately randomized to receive GONB (n = 51) or metoclopramide (n = 48). Efficacy was measured by improvement on a pain scale ranging from 0 to 10 completed both at baseline and after 1 hour.

Analyses revealed:

• Patients who received the GONB reported a mean improvement of 5.0 (95% CI, 4.1- 5.8) whereas those who received metoclopramide reported a larger mean improvement of 6.1 (95% CI, 5.2- 6.9)
• The 95% CI for the between-group difference of −1.1 was −2.3 to 0.1
• Sustained headache relief was reported by 11 of 51 (22%) GONB and 18 of 47 (38%) metoclopramide patients (95% CI for rounded difference of 17%, −1% to 35%)
• Of the 51 GONB patients, 17 (33%) required rescue medication in the ED vs 8 of 48 (17%) metoclopramide patients (95% CI for rounded difference of 17%, 0%-33%).
• An adverse event was reported by 16 of 51 (31%) GONB patients and 18 of 48 (38%) metoclopramide patients (95% CI for rounded difference of 6%, −13% to 25%).

“While GONB was not as efficacious as intravenous metoclopramide, an exploratory analysis suggested that in experienced hands, GONB and intravenous metoclopramide may have comparable efficacy,” researchers said.

For example, poor 1-hour pain outcomes were common when the provider had previously performed fewer than 7 GONB, while patients receiving the treatment from providers who had completed 7 or more GONB “almost uniformly reported >50% relief of pain.” The association established between health care provider experience and outcomes thus marks a limitation to the study. Researchers also caution against generalizing findings to the entire population of migraineurs presenting to EDs, as a large number of patients screened for the study did not meet inclusion criteria.

Reference

Friedman BW, Irizarry E, Williams A, et al. A randomized, double-dummy, emergency department-based study of greater occipital nerve block with bupivacaine vs intravenous metoclopramide for treatment of migraine. Headache. Published online September 27, 2020. doi:10.1111/head.13961