Cocaine can indeed be ingested with some notable effects - in parts of South America, they drink coca tea with effects similar to caffeinated tea. In fact, there's evidence to suggest that cocaine is safer as as stimulant than caffeine is - the main difference as we perceive it is the means of ingestion (we're used to thinking of caffeine as something you drink - very few people snort caffeine pills, which is very dangerous).
Also, chewing on cocaine leaves is used as a symptomatic treatment for altitude sickness in South America.
While in South America for a year I drank tons of Coca tea and chewed on the leaves a lot too.
For me, the effect was something like a red bull, but less instant. Kind of like that "second wind" you get sometimes late in the day where you have all kinds of energy you were not expecting.
I feel it genuinely did help with hiking at high elevations (above say 3500 meters, 12k ft) which I did a lot.
Which is kind of fun because I never noticed any effects from drinking caffeine beverages. So I just drink them for taste.
Would that mean I'll not notice cocaine either?
Not necessarily, because the two drugs are metabolized through completely different channels and, other than the fact that both are stimulants, have very different effects (ie, the mechanisms by which they take their effect is very different).
You may just have an abnormally high tolerance to caffeine, but there's no reason to suspect that that would carry over to cocaine, as cocaine targets both the D1 and D2 receptors, and caffeine provides cross-tolerance only to drugs which target one XOR (exclusive or) the other[0].
Also, chewing on cocaine leaves is used as a symptomatic treatment for altitude sickness in South America.
As for the actual bioavailability, take a look at this Bluelight thread: http://www.bluelight.ru/vb/threads/394593-Bioavailability-of...