Nimodipine transfer into human breast milk and cerebrospinal fluid

To report nimodipine concentrations in breast milk and cerebrospinal fluid (CSF) of a lactating woman who was given the drug to prevent a vascular spasm secondary to angiographic examination.

A 36-year-old woman received a total dose of nimodipine 46 mg iv over 24 hours. She extracted milk when she noted mammary tightness, and blood samples were taken simultaneously by venipuncture in the arm contralateral to that of the nimodipine infusion. A CSF sample also was taken in a diagnostic lumbar puncture.

Nimodipine concentration in milk was much lower than that in serum, with a milk/serum ratio of 0.06-0.15. The CSF/serum ratio was 0.01. We estimate that the infant would have received between 0.008% and 0.092% of the weight-adjusted dose that was administered to the mother if the baby had been nursed.

Nimodipine is transferred to human milk in a lower proportion than are other calcium-channel blockers. These results suggest that treating the mother with nimodipine would entail no risk to the nursing infant.