High- vs Standard-Dose Intravenous Magnesium for Acute Headache

Intravenous Magnesium Sulfate Versus Paracetamol for the Treatment of Acute Non-Traumatic Headache in the Emergency Department: A Randomized Double-Blind Controlled Trial

Headache is one of the most common reasons for consultation in emergency departments and represents a significant cause of disability, particularly in patients with migraine and other primary headache disorders. Despite the availability of several analgesic treatments, including nonsteroidal anti-inflammatory drugs and paracetamol, pain relief is often incomplete, and a proportion of patients require additional rescue therapy.

Magnesium sulfate has emerged as a potential therapeutic option in acute headache due to its role in modulating neuronal excitability, vascular tone, and pain-related neurotransmitter release. However, its efficacy as a standalone treatment, the optimal intravenous dose, and its comparative effectiveness versus standard therapy remain unclear.

This randomized, double-blind, controlled trial aims to evaluate the efficacy and safety of intravenous magnesium sulfate in the treatment of acute non-traumatic headache in the emergency department. Participants will be randomly assigned to receive either low-dose magnesium sulfate (2 g IV), high-dose magnesium sulfate (4 g IV), or intravenous paracetamol (1 g IV) as an active comparator.

The primary outcome is the change in pain intensity measured using the Visual Analog Scale (VAS) at 60 minutes after treatment administration, as well as the proportion of patients achieving at least 50% pain reduction. Secondary outcomes include time course of pain relief, need for rescue medication, adverse events, patient satisfaction, and length of stay in the emergency department.

In addition, the study will assess baseline ionized magnesium levels to explore their relationship with treatment response and evaluate whether magnesium levels may predict clinical efficacy.

The results of this study may help clarify the role of intravenous magnesium sulfate in the management of acute headache and potentially improve treatment strategies in emergency settings.

Inclusion Criteria:

• Age ≥18 years

• Presentation to the emergency department with acute non-traumatic headache of less than 72 hours duration

• Diagnosis consistent with a primary headache disorder, including:

  • Migraine
  • Tension-type headache
  • Cluster headache (according to ICHD-3 criteria)

• Moderate to severe pain intensity (VAS ≥5/10)

• Ability to understand the study procedures and provide informed consent

Exclusion Criteria:

• Suspected or confirmed secondary headache (e.g., intracranial hemorrhage, infection, mass lesion)
• Recent head trauma
• Known hypersensitivity or contraindication to magnesium sulfate or paracetamol
• Use of analgesic medication within the previous 6 hours
• Pregnancy or breastfeeding
• Severe renal insufficiency or conditions contraindicating magnesium administration
• Hemodynamic instability or clinically significant cardiac conduction disorders Prior participation in this study