Rationale — Tissue-type plasminogen activator (tPA) is a double-sided molecule, with beneficial effect in acute ischemic stroke due to its intravascular fibrinolytic activity but with potential deleterious effect due to its ability to potentiate neuronal N-methyl-D-aspartate (NMDA) receptor signalling (Nicole et al., 2001). Co-administration of sub-anesthetic dose of ketamine - a non-competitive inhibitor of NMDA receptor - was shown to improve efficacy of tPA-mediated thrombolysis following stroke in rodents (Gakuba et al, 2011).