What is the recommended dosage of Ativan (lorazepam) for an adult patient with anxiety prior to an MRI (Magnetic Resonance Imaging) procedure?

Lorazepam Dosing for MRI Anxiety

For adult patients with anxiety prior to MRI, administer lorazepam 0.5-1 mg orally, taken 1.5-2 hours before the procedure to allow peak plasma levels during the scan, with a maximum single dose of 2 mg. 1, 2

Standard Adult Dosing

• The recommended dose is 0.5-1 mg orally, administered 1.5-2 hours before the MRI procedure to ensure peak anxiolytic effect during the scan 1, 2
• This timing allows the medication to reach therapeutic levels when the patient enters the scanner, as lorazepam requires time for oral absorption 2
• The maximum single dose should not exceed 2 mg for procedural anxiety 2

Elderly and Debilitated Patients

• Reduce the dose to 0.25-0.5 mg orally for elderly or debilitated patients, with a maximum of 0.5 mg per dose 3, 1, 2
• This population is at higher risk for excessive sedation and cognitive impairment 1

Alternative Administration Route

• Oral tablets can be used sublingually (off-label) if faster onset is desired, though this is typically unnecessary given the 1.5-2 hour pre-procedure timing 3, 1

Critical Safety Considerations

• Instruct patients to avoid alcohol entirely when taking lorazepam, as this combination significantly increases sedation, cognitive impairment, and risk of disinhibition or delirium 2
• Respiratory depression risk increases when combining lorazepam with other sedatives 2
• For patients with COPD or respiratory disease, use lower doses or consider alternative anxiolytics due to respiratory depression risk 2
• Paradoxical agitation occurs in approximately 10% of patients treated with benzodiazepines 1

Pre-Medication Counseling

Before administering lorazepam, address reversible causes of anxiety by exploring the patient's concerns about the MRI procedure, explaining what to expect during the scan, and ensuring effective communication 3, 1

Common Pitfalls to Avoid

• Do not administer lorazepam immediately before the MRI - the 1.5-2 hour window is essential for adequate absorption and peak effect 2
• Avoid prescribing doses higher than 2 mg for a single procedural event, as this increases side effects without proportional anxiolytic benefit 2
• Do not use lorazepam regularly for repeated MRI procedures, as tolerance, addiction, depression, and cognitive impairment can develop with regular use 1