Intravenous magnesium and methocarbamol for acute pain crises in refractory trigeminal neuralgia: A retrospective...

Despite optimized therapy, up to 30% of patients with trigeminal neuralgia (TN) experience treatment failure. To date, there is limited and low-quality data available on rescue strategies for this subset of patients. This study describes clinical outcomes associated with intravenous (IV) magnesium sulfate and methocarbamol, with or without adjunctive antiseizure medications (ASMs), in the management of acute, refractory TN pain crises.

This was a single-center, retrospective cohort study conducted at the Cleveland Clinic Headache and Facial Pain Section from January 2015 to 2024. We analyzed adults (≥18 years) with treatment-refractory TN who received a standardized 3-day infusion regimen of magnesium sulfate and methocarbamol, with or without IV ASMs (levetiracetam, lacosamide, or valproic acid). Each encounter represented a distinct TN pain crisis treated with 3 consecutive days of infusion therapy. Infusions were administered specifically during acute exacerbations of pain that occurred despite ongoing or previously attempted maintenance treatment. Pain intensity was assessed using the 11-point numerical rating scale before and after each infusion day. The primary outcome was the proportion of encounters achieving a ≥50% reduction in NRS score from day 1 preinfusion to day 3 postinfusion.

A total of 170 patients were included. The patient encounters analyzed in this study had an overall mean age of 57.0 years and consisted mostly of females (n = 130, 76.5%). A ≥50% reduction in pain score was achieved in 86.9% of encounters. The largest reduction occurred on day 1, with diminishing but continued improvements on days 2 and 3. Adjunctive IV ASMs were not associated with improved response compared to the magnesium and methocarbamol alone (72.4% vs. 75.8%, respectively; p = 0.740). Pain Disability Index scores also improved among patients with follow-up data.

A 3-day IV infusion protocol combining magnesium sulfate and methocarbamol, with or without adjunctive ASMs, was associated with rapid, meaningful pain relief in most patients with acute TN pain crises. Larger, prospective studies are warranted to further investigate and confirm the effectiveness of this IV treatment strategy for managing this challenging neurological condition.