Expert: Dr Ian Jackson - please note UK based - 3/7/2009

Question
QUESTION: Hi:

Let's say some fresh green coca leaves are ground into a fine paste. Can this fresh paste be used as a topical anesthetic [i.e numb the local skin and rubbing the coca paste on it]? Will it cause totally numb the skin in the area where it is applied?

What effects other than numbness would result? Tingling?


Thanks,

Green

ANSWER: Hi there
The degree of numbness would depend on the amount of cocaine in the paste but this is seldom above 1%. Then there would be the amount of time it was applied for and the ability of the paste to release the active ingredient so that it can penetrate the skin and reach the nerve ending it needs to numb.
Given the dangers of cocaine this is not something I have seen or read about being tried so the honest answer is I haven't a clue how effective it would be - I suspect not very.
It is used on mucous membranes which are much thinner than skin but mainly for its ability to constrict blood vessels to reduce bleeding e.g. in nose operations.
Sorry can't help much more than that - except to say we use agents such as EMLA Cream (Google it) which achieve the effect you describe but only for a short period.
Dr Ian Jackson

---------- FOLLOW-UP ----------

QUESTION: Hi and thanks for your response,

What is the most potent plant-based topical anesthetic?

Historically, the Incas used coca, while the Chinese used hashish.

Is EMLA cream the most potent of all topical anesthetics?

Does EMLA totally-numb the skin it is applied to? If so, could it be used to mitigate the annoying affects of allergies? There are times of the year when my nasal allergies are very irritating, it feels like a little monster is tickling it. If I can apply or spray a very strong topical anesthetic into my nose, I think this would help decrease the itching/tickling and prevent me from sneezing. Right?


Thanks again,

Green

Answer
Hi there
I suspect that cocaine in coca plants is the most potent.

No EMLA isn't the most potent there are other newer mixes of old compounds that act more quickly and effectively.

However non of them are suitable for nasal use and for many reasons this would be a bad direction to take trying to control allergies.

It is much better to attempt to control these with nasal steroid sprays and the use of some agents that vasoconstrict the nasal mucosa. Cocaine certainly does the latter but the side effects and addiction is BAD! So don't go there.

Your mucous membranes that are causing the problem have an enormous surface area inside your head i.e. it is not just the front part that you have access to to apply any paste. So nasal sprays are the way forward.

Kind regards
Dr Ian Jackson