It may have been a year or two ago, but we had a shortage of MTX pill form. Its a real cheap drug and manufactures had huge back stocks quite a few quit making it. and suddenly there wasn't enough to go around and prices exploded. Folks started using it and it wasn't long before the reports started circulating about how much better it was. Sooner or later they started doing studies like this one: http://www.ncbi.nlm.nih.gov/pubmed/23982537
They also learned there were fewer side effects (stomach wise anyway) Docs are doing it a couple of different ways for patients. They are starting with lower doses of the injectable and working their way up, they are starting on pills and switching to injectable, if there is problem. The docs here are using a full dose from the get go of the injectable believing it has more efficacey quicker because the blood levels build faster.
The effect has been so dramatic in fact that the FDA recently approved a new drug called Otrexup late last year and just last month another one called Rasuvo that has more dosing options. They are basically MTX autoinjectors. I didn't realize what a fantastic thing this was until this last weekend. Until I saw Dr Peggy working with a group of 7 - 10 year olds and had them autoinject as a group (it was saline) Its been a bit of a battle with my grandaughter as she has learned to inject her self, but I have to draw it up. Seeing these kids take one more step for being independent and taking control of their disease was great.
There is an advantage to drawing your own meds especially for kids in that there is less preservative therefore less sting. The littler ones in particular have a different skin pH than us so all these things sting them a bit more. Sorry That was more than you asked for.