I've gotten drunk that night after having a concussion. Nothing went wrong.
To be safe, you probably should wait 48 hours (if that's what was medically advised). However, if we're talking 46 hours vs 48 hours, who gives a ****.
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Commodore
http://i941.photobucket.com/albums/ad258/CommodoreTN/CommodoreBrokemonpngtu.png