What is the recommended dose of nimodipine (calcium channel blocker) for patients with subarachnoid hemorrhage (SAH)?

Nimodipine Dosing in Subarachnoid Hemorrhage

The recommended dose of nimodipine for patients with subarachnoid hemorrhage is 60 mg orally every 4 hours for 21 consecutive days, starting within 96 hours of SAH onset. 1, 2

Standard Dosing Protocol

• Initial dose: 60 mg orally every 4 hours
• Duration: 21 consecutive days
• Timing: Start as soon as possible, within 96 hours of SAH onset
• Administration: Swallow capsules whole with a small amount of liquid, preferably not less than 1 hour before or 2 hours after meals 2

Alternative Administration Methods

For patients who cannot swallow capsules (e.g., unconscious patients or during surgery):

• Make a hole in both ends of the capsule using an 18-gauge needle
• Extract contents into an oral syringe (clearly labeled "Not for IV Use")
• Administer via nasogastric tube or PEG
• Flush with 30 mL normal saline 2

Dose Adjustments

Hypotension Management

• Hypotension is common (occurring in up to 78% of patients) 3
• If significant hypotension occurs:
  1. First, consider maintaining the dose with vasopressor support (after aneurysm occlusion) 4
  2. If necessary, reduce dose to 30 mg every 4 hours 2
  3. Monitor blood pressure closely, as significant drops in diastolic BP (>20% from baseline) are associated with unfavorable outcomes 4

Liver Dysfunction

• For patients with severe liver dysfunction or cirrhosis:
  • Reduce dose to 30 mg every 4 hours
  • Monitor blood pressure closely
  • Consider discontinuation if hypotension persists 2

Elderly Patients

• Plasma concentrations may be approximately 2 times higher in elderly patients
• Monitor closely for hypotension
• Consider dose reduction if necessary 4, 2

Important Considerations

• Never administer nimodipine intravenously - severe hypotension may result 2
• Avoid grapefruit juice during treatment 2
• Maintain consistent administration even with mild hypotension, as disruption is associated with increased delayed cerebral ischemia 4
• Maintain euvolemia rather than hypervolemia or hypovolemia 1, 4
• Only 33-43% of patients complete the full 21-day course at full dose due to hypotension 5, 6
• Oral solution formulations may cause more frequent blood pressure drops than tablets 7

Clinical Evidence and Rationale

Nimodipine is the only FDA-approved drug for neuroprotection in SAH patients. It works through neuroprotective effects rather than primarily through vasodilation 4, 2. Multiple randomized controlled trials have demonstrated that nimodipine reduces the risk of delayed cerebral ischemia and improves functional outcomes after SAH 1, 2.

The American Heart Association/American Stroke Association guidelines (2023) strongly recommend early initiation of enteral nimodipine to prevent delayed cerebral ischemia and improve functional outcomes after aneurysmal SAH 1.

Common Pitfalls

• Using other calcium channel blockers instead of nimodipine (only nimodipine has strong evidence) 4
• Discontinuing nimodipine at hospital discharge before completing the 21-day course 5
• Excessive dose reductions or discontinuation due to hypotension, which may be associated with unfavorable outcomes 6
• Failure to monitor for hypotension, especially in elderly patients or those with liver dysfunction 4, 2
• Intravenous administration (which is contraindicated and dangerous) 2