Pharmacokinetic and Pharmacodynamic Profiles of Intravenous and Enteral Nimodipine in Patients with Aneurysmal Subarachnoid Hemorrhage: A Scoping Review

Background: Nimodipine is routinely used in aneurysmal subarachnoid hemorrhage (aSAH), but the optimal route of administration remains uncertain. Intravenous and enteral delivery differ in pharmacokinetics, yet the clinical relevance of these differences is unclear. This scoping review aimed to map evidence on the pharmacokinetics (PK) and pharmacodynamics (PD) of intravenous and enteral nimodipine and their relationship with clinical outcomes. Methods: A scoping review was conducted following PRISMA-ScR guidelines. PubMed, Scopus, and Web of Science were searched from 1982 to March 2026. Studies in adult aSAH patients reporting PK and/or PD outcomes after intravenous or enteral nimodipine were included. Data were synthesized qualitatively. Results: Twenty studies were included. Intravenous administration provided higher and more consistent systemic exposure, whereas enteral administration showed low and highly variable bioavailability, particularly via nasogastric tubes. Despite these differences, pharmacodynamic effects were not clearly related to systemic concentrations, and hypotension occurred similarly across routes. Evidence on cerebral physiology was limited. Randomized studies showed no significant differences in delayed cerebral ischemia, infarction, or functional outcomes between routes. Conclusions: Pharmacokinetic advantages of intravenous nimodipine do not consistently translate into pharmacodynamic or clinical benefits, although available evidence is limited and heterogeneous. The PK-PD relationship appears weak, and further research is needed to guide optimized administration strategies.