Venlafaxine
"I began on a low dose of the ER 37.5 & immediately noticed the dry mouth, headaches and burning pit in my stomach 24/7.  Then came the blurry vision, urinary issues &  by day 10, the most debilitating stiff & painful back you can imagine. I knew it had to be related to the meds since this is NOT a Fibro symptom (at least for me) nor did I do anything to injure  myself. Before I discovered it was the meds I had gone to a walk in clinic (or hobble in clinic) & was given muscle relaxers. Nothing worked. Not ibuprofen, hot or cold compresses or muscle relaxers. After researching further I found that this medication can cause severe muscle stiffness.  I then asked my Dr.'s nurse if this was true and she said yes, she experienced it herself."