Why didn't Akame die when she cut herself with Murasame? As per the wiki, Murasme ...


  ... is a poisonous blade that can kill a person with only one cut. Once the sword pierces skin, it injects a lethal poison into the victim, killing them within seconds. Akame states that cleaning this weapon is very dangerous because of this ability.


In the anime, episode 24 to be exact, she cuts herself when fighting Esdeath to get a massive power boost for a few minutes by supposedly using the strength of all the people she has killed. Based on what I've seen in the anime and the discussions around the blade, she should have died, why didn't she?
It indeed is very confusing.

In episode 4 of the anime, Akame tells this to Tatsumi in the alley:


  Maintaining it is nerve-raking


referring to her sword. She continues and says


  If you accidentally cut your finger, you die instantly


Keeping the above in mind, I think there are three possibilities:


She was not aware of the hidden power of the sword at that moment (in episode 4) and later on found that she can cut herself to get the cursed power for a short period. This behavior of an imperials arm has been seen at other places too, where Esdeath did not initially know that she can stop time, but she learned that after Tatsumi escaped her.
She knew that if she cuts herself with her sword, she would get the cursed powers, but at that moment in episode 4, she wanted to signify that even an invincible looking imperial arms can have weaknesses.
The last possibility is that the hidden ability of the sword cannot be simply invoked. So when she actually does not want to use the hidden ability and she gets cut by the sword, she might die.


Furthermore, in the last episode, while using the hidden ability, Akame thinks


  Even if this consumes me


which indicates that prolonged/over use of the ability might lead the user to get consumed by the curse itself.

In any of three scenarios, I think the anime overall was really nice and it just left some open ended questions to the imagination of the viewers.