Tranexamic acid (TXA) and ε-aminocaproic acid (EACA), two antifibrinolytic drugs used to minimize blood loss during surgery, can cause seizures. A recent study (J. Clin. Invest. 122, 4654–4666, 2012) identifies glycine-receptor inhibition as a possible mechanism for this side effect and suggests a possible way to prevent it.

TXA and EACA bear some structural similarity to glycine, inhibition of which triggers epilepsy. Might both compounds promote seizures by interfering with glycine-mediated neurotransmission? Studying mouse neurons and brain slices, Irene Lecker et al. found that, indeed, both drugs competitively antagonize glycine receptors. Moreover, the concentration of TXA in the cerebrospinal fluid of patients undergoing surgery was similar to concentrations with inhibitory potency in vitro.

As patients treated with TXA and EACA often experience seizures after coming out of anesthesia, the authors went on to show that the anesthetics isoflurane and propofol reduced the inhibitory effect of the antifibrinolytic drugs. This observation raises the possibility of using these general anesthetics to prevent TXA- and EACA-induced epileptic activity.