Don't use the wrong vitamin K.

The emergency use of vitamin K is essentially limited to the reversal of drug-induced hypoprothrombinemia. In patients with adequate liver function, phytonadione acts promptly and predictably in this capacity whereas the derivatives of menadione counteract coumarin drugs only slightly or not at all. It is dangerous to rely on menadione analogues, and these drugs should be removed from emergency room drug stores.