Pharmacology · Calcium channel blockers
Nimodipine !
A lipid-soluble dihydropyridine given by mouth after subarachnoid haemorrhage to reduce damage from delayed ischaemia. Never given IV from capsules.
Updated 2026-11-01
The figure shows amlodipine, another dihydropyridine, in the same binding site of the human CaV1.2 channel; no human structure with nimodipine bound is available.
Mechanism of action
Nimodipine blocks L-type calcium channels and, being highly lipid-soluble, reaches cerebral arteries well. After aneurysmal subarachnoid haemorrhage it reduces neurological deficits from delayed ischaemia; how it does so is not fully known, since it does not clearly reverse the angiographic vasospasm. It also lowers systemic blood pressure.
- Nimodipine crosses into the brain and blocks L-type calcium channels
- Less calcium entry in cerebral vessels and neurons
- Fewer deficits from delayed ischaemia after the bleed
Pharmacokinetics
- Absorption
- Large first-pass loss, so bioavailability is low; food lowers it further
- Metabolism
- Liver, by CYP3A4
- Half-life
- Short early elimination, so it is given every 4 hours
Indications
- Aneurysmal subarachnoid haemorrhage, to improve neurological outcome Subarachnoid haemorrhage →
Adverse effects
Common
- Hypotension
- Headache
- Nausea
- Flushing and oedema
Contraindications
- Use with strong CYP3A4 inhibitors (some macrolides, azole antifungals, HIV protease inhibitors, nefazodone)
Key interactions
- Strong CYP3A4 inhibitors
- Marked hypotension; contraindicated
- Strong CYP3A4 inducers (for example rifampicin, carbamazepine, phenytoin)
- Much lower levels and loss of effect
- Grapefruit juice
- Stronger and longer blood pressure lowering
What is monitored
- Blood pressure and heart rate, often
- Neurological status
Administration and safety
- By mouth or feeding tube only, never IV or by any other injection
- If the patient cannot swallow, capsule liquid is moved into an oral syringe that cannot take a needle, labelled for oral or tube use
- Given every 4 hours, preferably away from meals; grapefruit is avoided
- Several «-dipine» names look alike (nifedipine, nicardipine): the name is checked on every order
Nursing care
- Check blood pressure before each dose and follow the protocol if it falls
- Assess neurological status regularly and report any new deficit
- Make sure only oral syringes are used for capsule contents
Pregnancy and breastfeeding
Human data are limited; it is used in pregnancy only when the benefit justifies the risk.
Test yourself
Think of the answer, then tap the question to see it.
What is the main indication of nimodipine?
Aneurysmal subarachnoid haemorrhage, to reduce neurological deficits from delayed ischaemia.
What happens if the contents of a nimodipine capsule are injected IV?
Severe cardiovascular events, including collapse, cardiac arrest and death; it is given only orally or by tube.
Which drugs are contraindicated with nimodipine?
Strong CYP3A4 inhibitors such as clarithromycin, ketoconazole or ritonavir, because of significant hypotension.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - NIMODIPINE capsule, liquid filled (DailyMed (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 31 (McGraw Hill, 2023).
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Representative model, for educational purposes only.