Hmm, not sure about the 12mgs in shot form. I get .6cc's in shot form. There was a time when I was taking 8 pills per week which equal 20mgs of methotrexate. If I remember right 6cc's is = to 6 pills which would be 15mgs. Maybe someone out there knows more. I use to be really afraid of methotrexate and still struggle with having to take it but I have gone without it for up to 3 weeks and believe me it has made a difference in my life. Also I have tolerated the shots soooo much better, I hardly have any side effects now. Methotrexate is one of the better medications to be on... the lesser of the evils so to speak. I hope you get some answers. Sorry I couldn't help more.
For I know the plans I have for you declares the Lord, plans for good and not evil to give you a future and a hope. Jeremiah 29:11