Idiomatic equivalence is a term used to refer to words or phrases that are used in a country, but with the meaning related to the culture of the country and not the actual meaning of the word, such as "break the leg" that is used in the United States as a wish of good luck. A failure in idiomatic equivalence occurs when a foreign person does not know the cultural meaning of the word or phrase and understands the word with its literal meaning, causing much confusion, as can be seen in the question above.
Thats a very vague question, since sleep medication itself is supposed to cause loss of consciousness, by try either blackout, overdose, or misuse. If theres more to the question that may help narrow down the answer, let me know!
