Enteral or parenteral nimodipine treatment: a comparative pharmacokinetic study

BACKGROUND AND STUDY AIMS/OBJECT: Oral nimodipine is recommended to reduce poor outcome related to aneurysmal subarachnoid hemorrhage (SAH). In addition, animal experiments and clinical trails revealed a beneficial effect of enteral and parenteral nimodipine for the regeneration of cranial nerves following skull base, laryngeal, and maxillofacial surgery. Despite these findings there is a lack of pharmacokinetic data in the literature, especially concerning its distribution in nerve tissue.

Samples were taken from a consecutive series of 57 patients suffering from skull base lesions and treated with nimodipine prophylaxis from the day before surgery until the seventh postoperative day. Both groups received standard dosages for enteral (n = 25) and parenteral (n = 32) nimodipine . Nimodipine levels were measured in serum, cerebrospinal fluid (CSF), and tissue samples, including vestibular nerves.

Nimodipine levels were significantly higher following parenteral as compared with enteral administration for intraoperative serum (p < 0.001), intraoperative CSF (p < 0.001), tumor tissues (p = 0.01), and postoperative serum (p < 0.001). In addition, nimodipine was significantly more frequently detected in nerve tissue following parenteral administration (Fisher's exact test, p = 0.015).

From a pharmacokinetic point of view, parenteral nimodipine medication leads to higher levels in serum and CSF. Furthermore, traces are more frequently found in nerve tissue following parenteral as compared with enteral nimodipine administration, at least in the early course.