Ceftriaxone-induced Encephalopathy: A Pharmacokinetic Approach

We report a case of ceftriaxone-induced encephalopathy correlated with a high concentration of the drug in cerebrospinal fluid (CSF). Cephalosporin neurotoxicity is increasingly reported, especially in association with fourth-generation cephalosporins. The factors influencing CSF concentration are plasma concentration, liposolubility, ionization, molecular weight, protein binding and efflux. In our patient, high levels of ceftriaxone (27.9 mg/l) were found in CSF. β-Lactam-associated neurotoxicity is mainly due to similarities between GABA and the β-lactam ring. Because of differences in CSF/plasma ratios and blood–brain barrier efflux among patients, plasma drug monitoring cannot be used to estimate CSF concentration. As far as we know, this is the first reported case of ceftriaxone-induced encephalopathy associated with a high CSF concentration. LEARNING POINTS: Ceftriaxone dose adjustment and clinical surveillance are strongly recommended in patients with renal failure. Measuring ceftriaxone cerebrospinal fluid concentration could be useful for confirming ceftriaxone-induced encephalopathy.