Nimodipine
Brand name: Nimodip, Nimodipine SR, etc.
Drug class: Dihydropyridine calcium‑channel blocker (C⁺‑channel blocker).
---
1. What is Nimodipine used for?
| Condition | Typical use | Typical dose |
|-----------|-------------|--------------|
| Cerebral vasospasm after subarachnoid hemorrhage (SAH) | Prevention and treatment of delayed cerebral ischemia | 60 mg orally every 4 h (≈ 240 mg/day) for 21 days, often started within 24 h of aneurysm repair. |
| Migraine prophylaxis (off‑label) | Reduces migraine frequency in some patients | 60 mg/day in divided doses (often 60 mg QID). |
| Hypertension (off‑label) | In certain cases where other agents are contraindicated | 60 mg/day, but not the first‑line therapy for HTN. |
Note: The FDA‑approved indication is only for SAH. All other uses are off‑label.
---
2. How does it work?
- Nimodipine blocks voltage‑gated L‑type calcium channels in smooth muscle cells.
- This inhibits calcium influx, causing vasodilation—especially in cerebral vessels.
- It reduces intracranial vasospasm and improves cerebral blood flow.
---
3. How is it taken?
- Form: Oral tablets (usually 30 mg or 60 mg).
- Schedule: QID (every 4 h) for SAH.
- Food: May be taken with or without food; food does not significantly alter absorption.
- Hydration: Encourage adequate fluid intake to help maintain blood pressure.
---
4. Common side effects
| Symptom | Frequency / Notes |
|---------|-------------------|
| Headache | Common; often the first symptom to appear. |
| Flushing | Warmth or redness of the face. |
| Dizziness / Light‑headedness | May be more pronounced when standing up (orthostatic hypotension). |
| Palpitations / tachycardia | Reflex tachycardia can occur due to lowered BP. |
| Nausea / abdominal discomfort | Rare but possible. |
Serious but rare:
- Severe hypotension, syncope, worsening heart failure.
- Angioedema (very rare).
---
5. Drug interactions
| Interaction | Why it matters | What to monitor / adjust |
|-------------|----------------|--------------------------|
| CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, ritonavir) | Inhibit metabolism → ↑ nimodipine levels | Check BP; consider dose reduction. |
| CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin) | Increase metabolism → ↓ efficacy | May need dose adjustment or alternative therapy. |
| Other vasodilators / antihypertensives (ACE inhibitors, ARBs, beta‑blockers, nitrates) | Additive BP‑lowering effects | Monitor BP; avoid excessive hypotension. |
| Caffeine / stimulants | May blunt vasodilatory effect | Less clinically significant, but can affect BP. |
---
6. Contraindications & cautions
- Hypotension: Avoid if SBP < 90 mm Hg or DBP < 60 mm Hg.
- Second‑degree AV block, sick sinus syndrome: Contraindicated (especially with β‑blockers).
- Severe hepatic impairment: Reduced clearance → increased exposure.
- Pregnancy: Category B; use only if benefits outweigh risks.
- Breastfeeding: Drug excreted in milk; caution advised.
- Elderly: Greater sensitivity to hypotension; dose monitoring recommended.
---
7. Patient counseling points
- Take on an empty stomach? No; food does not affect absorption significantly.
- What to do if a dose is missed: Take it as soon as remembered; if it's close to the next dose, skip the missed dose.
- Watch for low blood pressure: Check your BP at home, especially in the morning and after standing.
- Report serious symptoms: Syncope, chest pain, severe headache, or signs of an allergic reaction (swelling, difficulty breathing).
- Do not abruptly stop: Especially if you’re on it for SAH; stopping may precipitate rebound vasospasm.
---
8. Quick FAQ
| Question | Answer |
|----------|--------|
| Can I take nimodipine with my antihypertensives? | Yes, but watch for additive BP lowering. |
| Is it safe during pregnancy? | Category B; use only if essential. |
| What if I have a heart block? | It’s contraindicated. |
| How long will I stay on it for SAH? | Usually 21 days after aneurysm repair. |
| Will it help my migraine? | Some patients benefit, but it’s not FDA‑approved for migraine. |
---
Bottom line
Nimodipine is a potent, selective cerebral vasodilator mainly reserved for preventing delayed cerebral ischemia after subarachnoid hemorrhage. It must be dosed carefully, monitored for hypotension, and adjusted for drug–drug interactions. Use only as directed by your healthcare provider, and keep a close eye on blood pressure and any signs of adverse reactions.