What is the recommended dose of nimodipine (Calcium Channel Blocker) for Subarachnoid Hemorrhage (SAH)?

Recommended Dose of Nimodipine for Subarachnoid Hemorrhage

The recommended dose of nimodipine for subarachnoid hemorrhage is 60 mg orally every 4 hours for 21 consecutive days, starting within 96 hours of SAH onset. 1, 2, 3

Administration Details

• Route: Oral administration (capsule form)
• Dose: 60 mg (two 30 mg capsules) every 4 hours
• Duration: 21 consecutive days
• Timing: Should be initiated as soon as possible within 96 hours of SAH onset
• Administration timing: Preferably not less than one hour before or two hours after meals 3

Alternative Administration Methods

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

1. Make a hole in both ends of the capsule using an 18-gauge needle
2. Extract contents into a syringe designed for oral administration (not IV)
3. Label syringe "Not for IV Use"
4. Empty contents into patient's nasogastric tube
5. Flush with 30 mL of normal saline (0.9%) 3

Important Warnings

• NEVER administer nimodipine intravenously or by other parenteral routes 3
• Inadvertent IV administration may cause significant hypotension requiring cardiovascular support
• Avoid grapefruit juice during treatment 3

Dose Adjustments

Liver Dysfunction

• Patients with severely disturbed liver function, particularly cirrhosis, require dose reduction to 30 mg every 4 hours with close BP monitoring 3

Hypotension Management

• Hypotension is a common side effect, occurring in up to 78% of patients 4
• Studies show that only 33-44% of patients complete the full 21-day course at full dose due to hypotension 5, 6
• If significant hypotension occurs:
  1. First attempt to maintain the dose while managing hypotension
  2. If necessary, reduce to 30 mg every 4 hours (50% dose reduction)
  3. Only discontinue if hypotension persists despite dose reduction 6

Clinical Considerations

• Maintaining the full dose is associated with better outcomes (OR 0.895, p=0.029) 6
• Oral tablets may cause less hypotension than oral solution formulations 7
• Consistent administration is crucial - disruption is associated with higher incidence of delayed cerebral ischemia 1
• Nimodipine works primarily through neuroprotection rather than vasodilation 2
• Nimodipine reduces the risk of cerebral ischemia and improves neurological outcomes, though it does not prevent angiographic vasospasm 1, 2

Comprehensive Management

Nimodipine administration should be part of a comprehensive management approach for SAH that includes:

• Maintenance of euvolemia (not hypervolemia) 1
• Blood pressure control (target systolic BP <160 mmHg) 2
• Early securing of the aneurysm 1
• Monitoring for vasospasm and delayed cerebral ischemia 2

Common Pitfalls

1. IV administration: Never administer nimodipine intravenously - this can cause severe hypotension
2. Premature discontinuation: Many patients are discharged before completing the 21-day course and not given prescriptions to continue at home 5
3. Hypotension management: Rather than discontinuing nimodipine, consider dose reduction and appropriate blood pressure management
4. Drug interactions: Strong CYP3A4 inhibitors should not be administered concomitantly 3

By following these guidelines, you can optimize nimodipine therapy for SAH patients while minimizing adverse effects and improving neurological outcomes.