Chlortrimeton - Vet prescribed and OTC the same?

As some of you know, I've been using Prednisolone for my cat's licky
granuloma, and the latest round hasn't been working, so I'm going to try
Derm Caps vitamins and 4 mg of Chlortrimeton. Does anyone know if the
over the counter name brand is the same compound as the generic sold by
1800petmeds.com? The descriptions are below as follows:

Generic:

Chlorpheniramine 4 Mg Tabs

Brand name:

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Active Ingredients
Chlorpheniramine Maleate 4 mg

Inactive ingredients:

Ingredients
D&C Yellow No. 10 Aluminum Lake, Lactose , Magnesium Stearate

I was planning to administer 2mg/2x a day (perhaps just 2 mg a day at
the
start).

Are the same inactive ingredients in the vet prescription?

Cheryl...

I've been told by my vet that they're the same. I tried the same
combination for Shamrock, but it didn't help, much like oral
steroids don't help him.

I take it that the diet change you or your mom was trying didn't
help? So frustrating!! The only thing helping Shamrock now is
Cyclosporine. We had to play with the dose, but 10mg seems to be
what his tummy can handle. He'd been off of it until I could get
10mg, and he was off for long enough that the lesions came back,
but he's been on 10mg daily now for a few weeks and the lesions are
calming down and he doesn't have his leg in the air all the time
any more (licking and biting his tail and back of one leg). When
the scabs are dry, I'm going to try him on every other day 10mg.
I've read articles (not from vets because this is an off-label use)
but from other cat slaves who use this that it's tricky to get the
dose right, and that at certain times of the year he may have to go
back on daily, but that at other times of the year he might be able
to benefit from every 3rd day. It's very expensive, and there are
so many reasons NOT to use it, but when nothing else works, and
this does, to me it's worth it to keep him comfortable.

Best wishes and good luck!