Switching brand of finasteride

I’ve been prescribed finasteride by my dermatologist and I’ve been taking it since the 1st of Jan, about more than 3 weeks ago. I’ve also been using Ketoconazole 2% since then for my dandruff & itchiness. Helps alot! So far I’ve been shedding and hair seems thinner, but im being optimistic & hoping for regrowth at the 6-8 month mark. My crown feels like its thickening up, but my temples & the frontal area seem thinner now, could even see my scalp under light…. Anyways, I was just curious if I could use another type of brand of finasteride once the one I’m currently taking is finished in March.

In theory, all drugs cleared by the FDA should be the same as the label states; however, I have heard complaints from some men who switched brands find that the effectiveness has changed. I don’t understand this other that some of these brands could be counterfeits, something more common than most of us realize.