Am I Safe to Use This Topical Steroid Cream/Ointment (Contains Also Neomycin)?

Dear Dr Nagler,

I have a very small patch of psoriasis on the glans of my penis and have been prescribed a topical steroid cream and at a later date an active form of vitamin D (Calcitriol) as an ointment to treat it. I occasionally use both as if it gets too out of hand the Calcitriol struggles to get it under control, but appears to be adequate for maintaining it when it is.

I would consult my local doctor who prescribed them, however, I am in another country for at least the next 6 months.

- Topical Steroid Cream:
Betamethasone valerate 1mg/g (0.1% w/w) Neomycin sulphate 5mg/g (0.5% w/w) (also contains: chlorocresol 1000, cetostearyl alcohol, white soft paraffin, liquid paraffin, sodium acid phosphate, phosphoric acid, sodium hydroxide and purified water)​

I have looked at the document you linked previously (below) and I notice it mentions neomycin, which leads me to believe that perhaps I shouldn't be using that cream (although I haven't for a while now). However, it does say by vein, by injection, or by mouth, when I'm only applying it topically, although to a fairly thin area of skin.
https://www.tinnitustalk.com/attachments/drugstoavoid-pdf.33350/

I actually just found the following as well:

"Neomycin is the drug that is most toxic to the structure involved in hearing, the cochlea, so it is recommended for topical use only. But even topical therapy has resulted in hearing loss when large areas were treated which allowed for large amounts of the drug to be absorbed into the body. Hearing loss caused by this class of antibiotics is usually permanent."
http://hlaa-sbc.org/wp-content/uploads/2013/11/Ototoxic_Brochure.pdf ​

It specifically relates to hearing loss, not tinnitus, but I guess seeing as they're interlinked it might be pertinent to both? Again, it says only recommended for topical use, but not for large areas, well, it's a very small area I have been using it on, but of thinner skin. I generally will apply it once a day for perhaps a week, at which point I can normally keep it under control for a fair while.

- Active form of vitamin D ointment:
Silkis:
Calcitriol 3 micrograms/g (also contains liquid paraffin, white soft paraffin, alpha tocopherol)​

The only mentions I can find for this one are in the following document it says:

"Vitamin D2 (Ergocalciferal)" [which I'm not sure how similar it is?]
https://www.ata.org/sites/default/files/Drugs Associated with Tinnitus 2013_Updated2017.pdf​

And page 16 of this document states vitamin d (calcitriol), but only has the number 3 as its code which refers to

"The vertigo generating action only, without any evident toxic action on the hearing apparatus." (page 8):
https://www.europeanreview.org/wp/wp-content/uploads/956.pdf​

Please could I have your thoughts as to whether either of these are safe. I must admit, from what I've read about neomycin in the topical steroid, I think I already feel pretty unsure about using it even if it seems to be safe based on the details that document specified. I suppose it might be possible to get a topical steroid without it as neomycin appears to be an antibiotic for bacteria, as opposed to specifically treating skin conditions (which the betamethasone valerate is for).

Thank you so much for all of the help you do.

Kind regards,
Michael

 

Hello @MichaelP -

Thank you for your excellent question.

Let's first consider the neomycin. The topical preparation you describe contains "Neomycin sulfate 5mg/g," which means it contains 5mg of neomycin per gram of cream or 75mg of neomycin in a 15 gram tube of cream. Neomycin ototoxicity is dose-related. Neomycin sulfate is not available for intravenous administration in humans, but veterinarians use it in doses of 2-4mg/kg 2-3x/day. In a human that would be the equivalent of roughly 750mg/day in divided doses. So even if 100% of your cream applied topically was absorbed as if it were administered intravenously (which is obviously far from the case in actuality), we are talking here about applying in the neighborhood of ten entire tubes of the cream each day to your "very small patch of psoriasis." To be extra conservative in this analysis, you could apply one entire tube a day without being concerned about otoxicity. So in my opinion you are fine in that regard.

As far as Vitamin D is concerned, as far as I know it does not have the potential to cause auditory damage in any routinely prescribed amount.

Hope this helps.

Stephen M. Nagler, M.D.