Benzocaine in shaving cream?

[David J. Kanter]

I heard that some new shaving creams have benzocaine in them, and that
some people swear by them. I've used some, and they do a decent job, but I
have some questions:
First, is long-term benzocaine use bad for you? Sometimes I get the
cream on my lips, which are subsequestly numbed. Is this bad?
Second, the claim is that benzocaine raises the hairs, making for a
closer shave. Is this a load a crap?

Thanks,

Dave

David J. Kanter
Northwestern University, Evanston, IL. USA
djka...@nwu.edu

[smarm]

In <4jrdo7$kq4...@nuts.nwu.edu>, djka...@nwu.edu (David J. Kanter) writes:
> I heard that some new shaving creams have benzocaine in them, and that
>some people swear by them. I've used some, and they do a decent job, but I
>have some questions:
> First, is long-term benzocaine use bad for you? Sometimes I get the
>cream on my lips, which are subsequestly numbed. Is this bad?

Long term use of benzocaine probably isn't bad for you. Getting it on your lips
isn't bad either but you do need to be careful with hot foods and liquids until the
local anesthetic effect wears off. Benzocaine is the most widely used topical
local anesthetic in the US and probably the world. However, are some problems
associated with the use of benzocaine.

1. Benzocaine is the most likely of the local anesthetics to produce a sensitivity reaction.
This response is similar to an allergic reaction. IOW, Some people have a reaction to
benzocaine that is similar to an allergic reaction. It produces itching, a rash, etc. It's
a rather unpleasant reaction. Shaving, and therefore irritating the skin, would make this
even worse.

2. Also, benzocaine is metabolized to p-aminobenzoic acid (PABA). Bacteria use
PABA to make folates. Humans don't use PABA. The problem is that the sulfonamide
antibiotics are designed to prevent the utilization of PABA by bacteria. Thus the
use of benzocaine laced shaving cream could decrease the efficacy of the sulfonamide
antibiotics. It seems unlikely, but with repetitive topical application of benzocaine, especially
to skin thats been shaved, thus increase transdermal absorption, enough benzocaine
could be absorbed to reduce the efficacy of the sulfonamides.

One problem with hiding a drug in a personal product like this, is that people don't
consider themselves as using a drug, when in fact they are.

>Second, the claim is that benzocaine raises the hairs, making for a
>closer shave. Is this a load a crap?

Don't know about this.

I have read, in patent lit., that vasoconstrictors have been added
to shaving cream to lessen bleeding from nicks. Don't know if this
combination ever made it to market though.

If you want to soothe your skin after shaving, go to your pharmacy and
buy Caladryl Clear (generic is cheaper!) and use it after shaving instead of lotion.
It contains the local anesthetic pramoxine HCl, which is much less likely to
cause a sensitivity reaction than benzocaine. It has a soothing effect and it
doesn't smell. Much less expensive than those fancy after shave lotions.

Michael Smar
College of Pharmacy
South Dakota State University
pc...@sdsumus.sdstate.edu