Epilepsy is defined as a group of concerning problems related to the nervous system; its defining feature is a predisposition to epileptic seizures. The frequency of seizures in intensive care units (ICU) ranges from 3.3% to 34%, and ICU antiepileptic treatment is routine practice. The administration of drugs through the same infusion line is not recommended but is common clinical practice, especially in ICU. Incompatibilities between parenteral drugs and between drugs and parenteral nutrition admixtures (PNAs) are common medical errors and pose risks to patient safety. The co-administration of drugs must always be confirmed and clearly defined. The simultaneous infusion of sodium valproate (VPA, drug used to treat seizures and epilepsy) with parenteral PNAs has not yet been studied. During the experiment reported in this study, a visual control, pH, osmolality, zeta potential, particle size, polydispersity index, and turbidity were measured. The conducted research shows that the lipid emulsion composition has a significant influence on drug–PN (drug–parenteral nutrition) compatibility. The acceptance criteria were met only for PNs containing omega-3-acid-triglycerides (Omegaflex special and peri). The second fraction of particles above 1000 nm was observed for most of the tested PNAs (Lipoflex special, Lipoflex peri, Kabiven, SmofKabiven, Kabiven Peripheral, and Olimel Peri N4E), which disqualifies their simultaneous administration with VPA.