Suddenly getting bad side effects from ketotifen after 9 months use?

My partner has been on ketotifen for 9 months now with no problem, increasing the dose always made them feel much better, very minimal side effects. A few weeks ago, they noticed they were starting to feel worse after taking it, so reduced the dose. It maybe helped for a bit, but now they're feeling awful after taking it. Their hands go ice cold like their blood pressure is tanking, they feel intense fatigue, brainfog, eye itchiness, etc. We're not sure what's wrong, if it's the long term use, their MCAS getting worse and reacting to the med, or their dysautonomia worsening and it being triggered by the ketotifen. Has anyone else been on ketotifen for a long time and suddenly gotten bad side effects? They've similarly started feeling much worse after Cromolyn, which makes us think it's more to do with their condition than the medicines.