Hi, I Have Been Taking A Dosage Of 100mg Twice

Hi, I have been taking a dosage of 100mg twice a day of minocyclin for nearly 2 years for the tratment of RA. Mostly the inflammation has been controlled. Beginning of September this year i reduced the doosage to 150mg daily, ie 100mg morning & 50mg at night, 3 weeks later I began to feel painful stiffness and inflammation in many joints. On 24/9/2015 I increased the dosage of the mino to 250mg, ie 100mg morning 50mg afternoon and 100mg evening. I thought i would increase the dosage to 250mg just for a week or so, since the increased dosage, the pain and inflammation is getting better.
Is the increased dosage to 250mg of mino considered safe and for how long?
Is minocycline a better option than Methotrxate for the treatment of RA?
Thank you very much
John