Is there evidence to suggest there is a withdrawal syndrome from muscle relaxants such as tizanidine?  

I have observed a trend where patients who are being tapered off of long-term benzodiazepine (especially in the geriatric population) prescriptions are more frequently receiving prescriptions for muscle-relaxant medications such as tizanidine and then experiencing worsening anxiety, panic, or other "withdrawal symptoms" when the muscle relaxants are stopped.

How would you approach experience of worsening anxiety and withdrawal prodromes when stopping muscle relaxants? Is there data to use longer-acting alpha-2 agonists (e.g., ER guanfacine)?