Expert: Ronald Levy, M.D. - 3/1/2010

Question
QUESTION: Hi:

What is the most potent topical anesthetic?


Thanks,

Green

ANSWER: What do you mean by potent? The best is probably Prilocaine (presription only) but benzocaine is also very effective.

Ronald Levy, MD
Professor of Anesthesiology
UTMB-Galveston

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

QUESTION: What about oxethazaine?

By "potent", I mean for the same amount, the numbing effect is stronger.

ANSWER: Oxethazine is not a drug that is available in the US (to my knowledge) but was sold under the name Mucaine. It has been around since the 60's but I don't know anything about it since it is not available here. We can't really talk about potency as you define it becuase it depends on the concentration I use more so than the amount. It's like saying "which is stronger, 1 800mg Ibuprophen or 1 50 mg Toradol". They're each 1 pill but the concentration is more important.

Ronald Levy, MD
Professor of Anesthesiology
UTMB-Galveston


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

QUESTION: Sorry.

For the same concentration, which topical anesthetic is the most potent? Is this anesthetic available in its pure molecular form?

From what I've read, Oxethazine is much stronger [for the same concentration] than EMLA. I don't known if it is the most potent, though.

It takes a much lower concentration of Oxethazine -- compared to EMLA -- to produce the same anesthetic effect as EMLA. Hence, Oxethazine is more potent than EMLA.

Potency here is defined as how intense the numbness will be for the same concentration of the anesthetic.


Thanks,

Green

Answer
Again, I am not familiar with Oxethazine so I can't tell you about the density of the block. The intensity of the numbness is not as important as the density or the duration. If an area is numb, it is numb. The question about a topical is how deep the block goes. More than that, I can't answer for you.

Ronald Levy, MD
Professor of Anesthesiology
UTMB-Galveston