My feet were my first symptoms when the spondy started getting with it back in '99. Twenty years previous, I had an episode of low back pain with no obvious trigger--lasted about 6 months and went away. It was blamed on plantar fasciitis and treated, but both feet ended up getting the PF release surgery. Once I made to a rheumy a few years after the last surgery, treatment was started for 'inflammatory arthritis' with a lean towards 'spondy'. Once I made it to starting a biologic that worked (another couple of years), the foot pain got somewhat better. Currently, on Cimzia (5th biologic) for PsA, foot pain is largely gone unless I have a work night that leaves me unable to sit for a rest during the shift. Pains in arches, pains in heels, some pain in Achilles, and pain in metatarsal heads (ball of foot)--bilaterally.
So, yes, foot pain got better on a biologic that worked. I only had foot pain persist on Remicade, but it didn't do any good for me anyway.
If you've had improvement on your biologic in other ways but foot pain got worse, might see a doc about that to make sure there isn't some injury...like a stress fracture? However, it sounds like you've only had what you are calling side-effects. This one may not be the one for you. If it's less than 6 months (the usual trial period barring major side-effects), might keep going to see if it gets better, or bail to something else. Or could these symptoms have been brewing for a time anyway and are flaring up before the biologic had a chance to start working? Sort of up to you and the rheumy. In any case, good luck. Gentle hugs.
