Dynacin and 4 months

I was on Dynacin for approximately 6 months when I started having severe joint pain. No doctor could figure out why. I was on medicines for rheumatoid arthritis with no effect. It got so bad that I could barely walk and could not even dress myself. Finally, about 4 months into my arthritis treatment, a resident in the emergency room where I was taken because my pain was so bad suggested that it may be an allergic reaction to the Dynacin. I discontinued use and 6 years later have had no more joint pain. I feel as though I should let anyone know about this possibility since it is not generally listed with the possible (even rare) side effects