Intravenous Magnesium Sulfate in Aneurysmal Subarachnoid Haemorrhage (IMASH)

This study has been completed.
Information provided by:
Chinese University of Hong Kong Identifier:
First received: July 26, 2005
Last updated: December 21, 2009
Last verified: July 2009
The IMASH trial is a simple, randomized, double-blinded, placebo-controlled, multi-center trial to answer the question: "Does intravenous magnesium sulfate improve clinical outcome after aneurysmal subarachnoid hemorrhage?"

Condition Intervention Phase
Subarachnoid Hemorrhage
Drug: Intravenous magnesium sulfate infusion
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Phase 3 Study (Multi-center, Randomized Controlled Clinical Trial) of Intravenous Magnesium Sulfate to Improve Outcome After Aneurysmal Subarachnoid Haemorrhage

Resource links provided by NLM:

Further study details as provided by Chinese University of Hong Kong:

Primary Outcome Measures:
  • Extended Glasgow Outcome Scale [ Time Frame: At six months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Incidence of clinical vasospasm [ Time Frame: Within first 14 days ] [ Designated as safety issue: No ]
  • Barthel Index [ Time Frame: At six months ] [ Designated as safety issue: No ]
  • Modified Rankin Score [ Time Frame: At six months ] [ Designated as safety issue: No ]
  • Modified National Institute of Health Stroke Score [ Time Frame: At six months ] [ Designated as safety issue: No ]
  • Other major complications requiring intensive care unit admission [ Time Frame: During first 14 days ] [ Designated as safety issue: Yes ]

Enrollment: 327
Study Start Date: June 2002
Study Completion Date: June 2009
Primary Completion Date: December 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: M
Intravenous magnesium sulfate infusion for 14 days.
Drug: Intravenous magnesium sulfate infusion
80mg per day
No Intervention: S
Saline infusion without additional magnesium sulfate.

Detailed Description:

Vasospasm worsen outcome in patients with aneurysmal subarachnoid hemorrhage (ASAH).

Magnesium is known to dilate cerebral arteries and to block N-methyl-D-aspartate receptors in the injured neurons.

Intravenous magnesium may prevent vasospasm after subarachnoid hemorrhage and may protect neurons against damage during established vasospasm.

The IMASH trial is a randomized, placebo-controlled, double-blinded, multi-center trial to evaluate the effect that intravenous magnesium sulfate infusion on the clinical outcome of patients with aneurysmal subarachnoid haemorrhage.


After obtaining randomisation code:

  • Start MgSO4 20 mmol over 30 minutes, followed by infusion of 80 mmol/day or equivalent volume of saline within 48 h after onset of symptom,
  • Study drug to be infused for 14 days from the day of hemorrhage (regarded as day 0).
  • Measure plasma magnesium concentration daily and perform transcranial Doppler to monitor blood flow velocities of both middle cerebral arteries and extracranial segment of the internal carotid arteries.
  • Plasma magnesium concentration in the IV MgSO4 group should be raised to 2.0-2.5 mmol/L or twice the serum baseline level. Patients that are randomized to saline infusion will only have their magnesium levels normalized if there is a clinical indication to do so.

Outcome assessment Primary outcome: Extended Glasgow Outcome Scale at six months Secondary outcome: Incidence of clinical vasospasm, Barthel Index; modified Rankin score, modified National Institute of Health Stroke Score, MCA velocities, other major complications

Study duration:

6 years with a refined sample size of 340 after analysis of pilot study data; with planned interim analysis.


Ages Eligible for Study:   18 Years to 80 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • ASAH (as indicated by CT scan or lumbar puncture and an intracranial aneurysm confirmed by computer tomographic or conventional angiography)
  • Within 48 hrs of ictus (hemorrhage event)

Exclusion Criteria:

  • Pregnancy
  • Major renal, hepatic or pulmonary disease
  • Major cardiac disease or recent myocardial infarct (< 6 months)
  • Age less than 18 years
  • Moribund condition on admission (defined as a patient that is in such a poor clinical condition that further active neurosurgical management would not be anticipated)
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Please refer to this study by its identifier: NCT00124150

Department of Surgery, The Chinese University of Hong Kong
Hong Kong, China, 852
Sponsors and Collaborators
Chinese University of Hong Kong
Principal Investigator: Wai S Poon, MB ChB FRCS Department of Surgery, The Chinese University of Hong Kong
  More Information

Additional Information:
Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: George KC WONG, Division of Neurosurgery, The Chinese University of Hong Kong Identifier: NCT00124150     History of Changes
Other Study ID Numbers: IMASH trial 
Study First Received: July 26, 2005
Last Updated: December 21, 2009
Health Authority: Hong Kong: Joint CUHK-NTEC Clinical Research Ethics Committee

Keywords provided by Chinese University of Hong Kong:
subarachnoid hemorrhage
magnesium sulfate

Additional relevant MeSH terms:
Subarachnoid Hemorrhage
Brain Diseases
Cardiovascular Diseases
Central Nervous System Diseases
Cerebrovascular Disorders
Intracranial Hemorrhages
Nervous System Diseases
Pathologic Processes
Vascular Diseases
Magnesium Sulfate
Anti-Arrhythmia Agents
Calcium Channel Blockers
Central Nervous System Depressants
Membrane Transport Modulators
Molecular Mechanisms of Pharmacological Action
Peripheral Nervous System Agents
Physiological Effects of Drugs
Reproductive Control Agents
Sensory System Agents
Tocolytic Agents processed this record on May 25, 2016