NIMODIPINE
Clinical safety rating: safe
Animal studies have demonstrated safety
Dihydropyridine calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cells, leading to vasodilation and reduced cerebral vasospasm.
| Metabolism | Hepatic via CYP3A4, also metabolized by CYP3A5 and CYP2C8 to inactive metabolites. |
| Excretion | Primarily hepatic metabolism (>90%); renal excretion accounts for <1% of unchanged drug; fecal excretion of metabolites accounts for ~50% of total elimination. |
| Half-life | Terminal elimination half-life is approximately 8-9 hours in adults (range 7-12 hours); may be prolonged in elderly or hepatic impairment. |
| Protein binding | 95-99% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.9-1.6 L/kg (mean ~1.2 L/kg); indicates extensive tissue distribution. |
| Bioavailability | Oral: 13% (range 5-30%) due to extensive first-pass metabolism. |
| Onset of Action | Oral: 30-60 minutes; intravenous: 5-10 minutes. |
| Duration of Action | Oral: 6-8 hours; intravenous: 2-4 hours for hemodynamic effects; clinical effect on vasospasm persists for 12-24 hours with continuous IV infusion. |
Oral: 60 mg every 4 hours for 21 consecutive days. IV: 1 mg/hour initially, increase to 2 mg/hour after 2 hours if tolerated, for 5-14 days.
| Dosage form | SOLUTION |
| Renal impairment | No specific GFR-based adjustments required; use with caution in severe renal impairment (CrCl < 30 mL/min) due to potential accumulation. |
| Liver impairment | Child-Pugh Class B or C: Reduce oral dose to 30 mg every 4 hours. IV: Reduce to 0.5 mg/hour initially; may increase to 1 mg/hour if tolerated. |
| Pediatric use | Not FDA-approved; limited data. For aneurysmal subarachnoid hemorrhage in children, some protocols use 0.5-1 mg/kg orally every 4 hours (max 60 mg/dose) or IV 0.5-2 mg/hour. |
| Geriatric use | No specific dose adjustment, but start at lower end of dosing range; monitor for hypotension and bradycardia due to decreased clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Strong CYP3A4 inhibitors can significantly increase levels Must be administered orally via nasogastric tube if patient cannot swallow.
| Breastfeeding | Nimodipine is excreted in human milk; M/P ratio not established. Due to potential for adverse effects in nursing infants (hypotension, calcium channel blockade), breastfeeding is not recommended during therapy or for 48 hours after last dose. |
| Teratogenic Risk | Pregnancy Category C. In animal studies, nimodipine caused embryotoxicity and teratogenicity at doses 0.3-1.0 times the human dose. First trimester: limited human data, risk cannot be excluded. Second/third trimesters: may cause fetal hypoxia and maternal hypotension; avoid use unless benefit outweighs risk. |
■ FDA Black Box Warning
None
| Common Effects | Decreased blood pressure Headache Increased heart rate Nausea Rash Stomach discomfort Edema swelling Muscle cramp |
| Serious Effects |
["Known hypersensitivity to nimodipine or any component of the formulation","Concomitant use with strong CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin, phenobarbital, St. John's wort)"]
| Precautions | ["Hypotension","Increased intracranial pressure","Hepatic impairment","Use with caution in patients with known hypersensitivity to nimodipine or other dihydropyridines"] |
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| Fetal Monitoring | Monitor maternal blood pressure and heart rate frequently; assess for signs of hypotension. Fetal heart rate monitoring recommended if used near term. Neurological assessment in pregnant patients with aneurysmal subarachnoid hemorrhage. |
| Fertility Effects | No human data on fertility. In animal studies, no adverse effects on fertility observed at therapeutic doses. |