Can only one shot of depo-provera medrol (methylprednisolone) for arthritis rheumatoid cause gain weight? how long does it last in the body?

Depomedrol (methylprednisolone): Won't gain weight long term from just 1 injection. Injection lasts typically 1-4 months.

It could: Hard to say how long it lasts because there are a variety effects and suppression of you own body's ability to make your own cortisone. Weight gain can come quickly and i would be careful with overeatimg with the steroid boost you get from that high dose you get with depomedrol (methylprednisolone).