Magnesium, methocarbamol infusion provides relief in trigeminal neuralgia

Key takeaways:

• 86.9% of patients saw a 50% or greater reduction in pain scores from day 1 to day 3.
• The addition of antiseizure medications to the infusion did not change these reductions.

MINNEAPOLIS — Patients with trigeminal neuralgia experienced relief with IV magnesium and methocarbamol, according to data presented at the American Headache Society 67th Annual Scientific Meeting.

“The pain is really devastating,” Bradley Ong, MD, an incoming PGY3 adult neurology resident at the Cleveland Clinic Neurological Institute, said during his presentation.

“These patients aren’t able to eat. They’re unable to talk. For the most part, quality of life is really poor,” he said.

Bradley Ong

When these patients come to Ong’s clinic, he said that they begin carbamazepine, oxygen, or carbazepine.

“However, the recent studies have shown that around 30% or a third of these patients actually still fail standard therapy,” Ong said, adding that many of these patients then have high ED utilization rates.

“We don’t have a go-to medication that we can actually give these patients,” he said. “You need something that’s well parameterized as an alternative, something that’s fast, something that’s safe and tolerable as well.”

Previous studies of antiseizure medications such as pnehytoin, fosphenytoin and lidocaine as alternative treatments for trigeminal neuralgia acute pain crises have not indicated any statistical significance or sufficient evidence, Ong said.

Ong and his colleagues adopted a regimen that includes three consecutive days of 2 grams of IV magnesium sulfate infused over 1 to 2 hours with 1,000 mg of intravenous methocarbamol infused over 30 to 60 minutes.

Some patients also received an antiseizure medication — 200 mg of lacosamide, 500 mg of levetiracetam or 1,000 mg of valproic acid — each administered intravenously over 20 to 30 minutes.

“Clinicians would look into patients’ comorbidities, patients’ overall risk profile, before choosing an antiseizure medication,” Ong said.

The retrospective cohort study included 236 infusion encounters, defined as a 3-day infusion course for acute trigeminal neuralgia pain crisis, from 170 patients between January 2015 and August 2024.

Overall, 86.9% of patients experienced a 50% or greater reduction in Numeric Rating Scale pain scores from day 1 pre-infusion to day 3 post-infusion. IV antiseizure medications did not yield any significant difference in these scores, Ong said.

Also, 89.4% of the cohort experienced a 30% or greater reduction in day-to-day Numeric Rating Scale pain score on day 1, which Ong called a “moderate but still clinically relevant” improvement for patients with acute pain crisis.

“The most benefit occurred on day 1, which might suggest a neuromodulatory effect for these patients,” Ong said.

The median decrease on day 1 was 6 points. On day 2, 67.4% of patients achieved a 30% or greater reduction with a median decrease of 4 points. On day 3, 63.1% achieved a 30% or greater reduction with a median decrease of 2.5 points.

“We also looked at functional outcomes,” Ong said.

The Median Pain Disability Index score fell from 44 to 36, with the largest gains in the occupation, recreation and social activity domains.

Adverse events included nausea (19%), dizziness (12%), pruritis (12%), drowsiness (12%), confusion (9%), tremors (6%), rash (6%) and shortness of breath/overload (6%), with 16% reporting “other,” classified as adverse events reported by one patient, including palpitations, oral numbness and hand tingling.

“Our 3-consecutive-day infusion of magnesium and methocarbamol offers rapid and meaningful pain relief for our patients,” Ong said. “Given its tolerability in an outpatient facility, I think this may serve as a practical transitional strategy.”

For more information:

Bradley Ong, MD, can be reached at neurology@healio.com.