Brief Answer: Rheumatologist s opinion, rare observation though. Detailed Answer: Hi and thanks for the query, Methotrexate has effects in reducing inflammation and is used at times to treat some inflammatory diseases like rheumatoid arthritis. It is true that this drug had a different indication in your case. It might be necessary however to try to recall if you were experience any joint pains or inflammatory, or any muscle fatigue or pain before onset of symptoms. It is also possible that maybe during the course of treatment, you might have developed a condition like polymyalgia rheumatica or some muscle illness, that was well controlled at that point by methotrexate though unplanned. Methotrexate withdrawal does not have as reported side effect muscle pain. It is however of interest to do tests like erythrocyte sedimentation to see if there is any chronic inflammation in the body. Measuring creatinine kinase levels specific for muscles could indicate any possible muscle destruction. A review by a rheumatologist might be required to ascertain any muscle disease (myopathy) that could have been controlled, by chance by methotrexate. Its rare however under normal circumstances to observe this with methotrexate. Thanks and kind regards. do not hesitate asking further questions in case of need. Kind regards. DR Bain.

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